The following Bible Dictionary and Encyclopedia definitions provide clear understanding of time in a Hebrew context.
From the time of the institution of the Mosaic law the month among the Jews was lunar. The cycle of religious feasts depended on the moon. The commencement of a month was determined by the observation of the new moon. The number of months in the year was usually twelve (1 Kings 4:7; 1 Chron 27:1-15); but every third year an additional month (ve-Adar) was inserted, so as to make the months coincide with the seasons.
"The Hebrews and Phoenicians had no word for month save 'moon,' and only saved their calendar from becoming vague like that of the Moslems by the interpolation of an additional month. There is no evidence at all that they ever used a true solar year such as the Egyptians possessed. The latter had twelve months of thirty days and five epagomenac or odd days." Palestine Quarterly, January 1889.
(From Easton's Bible Dictionary, PC Study Bible formatted electronic database Copyright © 2003, 2006 Biblesoft, Inc. All rights reserved.)
From the time of the institution of the Mosaic law downward the month appears to have been a lunar one. The cycle of religious feasts, commencing with the Passover, depended not simply on the month, but on the moon (Josephus, Ant. 3:10, 5); the 14th of Abib was coincident with the full moon (Philo, Vit. Mos. 3, page 686); and the new moons themselves were the occasions of regular festivals (Num 10:10; 28:11-14). The statements of the Talmudists (Mishna, Rosh Hash. 1-3) are decisive as to the practice in their time, and the lunar month is observed by the modern Jews. The commencement of the month was generally decided by observation of the new moon, which may be detected about forty hours after the period of its conjunction with the sun: in the later times of Jewish history this was effected according to strict rule, the appearance of the new moon being reported by competent witnesses . . . .
(From McClintock and Strong Encyclopedia, Electronic Database. Copyright © 2000, 2003, 2005, 2006 by Biblesoft, Inc. All rights reserved.)
One of the 12 divisions of a year, measured by the completed cycle in the changing of the MOON. Solomon had 12 governors over all Israel, who provided food for the king and his household; each made provision for one month of the year (1 Kings 4:7). The military divisions of Israel were also 12 in number, one for each month of the year, each division consisting of 14,000 men (1 Chron 27:1-15).
(From Nelson's Illustrated Bible Dictionary, Copyright © 1986, Thomas Nelson Publishers)
From the time of the institution of the Mosaic law downward the religious feasts commencing with the passover depended not simply on the month, but on the moon; the 14th of Abib was coincident with the full moon; and the new moons themselves were the occasions of regular festivals. Num 10:10; 28:11-14. The commencement of the month was generally decided by observation of the new moon. The usual number of months in a year was twelve, as implied in 1 Kings 4:7; 1 Chron 27:1-15, but since twelve lunar months would make but 354 1/2 days, the years would be short twelve days of the short twelve days of the true year, and therefore it follows as a matter of course that an additional month must have been inserted about every third year, which would bring the number up to thirteen. No notice, however, is taken of this month in the Bible. In the modern Jewish calendar the intercalary month is introduced seven times in every nineteen years.
(From Smith's Bible Dictionary, PC Study Bible formatted electronic database Copyright © 2003, 2006 by Biblesoft, Inc. All rights reserved.)
The seasons regulated the months, e.g. Abib the first month of the year was that of "ears of grain"; in the Passover in it, on the second day, the sheaf of harvest firstfruits was waved to the Lord (Lev 23:10-12,34-39; Joel 2:28). So the feast of tabernacles in the seventh month celebrated the ingathering of the autumnal fruits; so that a solar year must have regulated the months. The months were 12 (1 Kings 4:7), with an intercalary month every third year, not noticed in the Bible. The modern Jews have seven intercalary months in every 19 years, according to the metonic cycle adopted A.D. 360 . . . .
. . . The intercalary month was Veadar, i.e. the additional Adar. The variations between the lunar and the solar month, each of the lunar ranging over two solar months, prevent exact coincidence with our months. The barley harvest is not until the middle of April, so that Abib or Nisan, in which the Passover first sheaf was offered on the 15 th day, coincides with April. Josephus (Ant. 3:10 , section 5) says the Passover was while the sun is in Aries, which it does not enter until the end of March.
(From Fausset's Bible Dictionary, Electronic Database Copyright © 1998, 2003, 2006 by Biblesoft, Inc. All rights reserved.)
The Hebrew or Jewish calendar had three stages of development: the preexilic, or Biblical; the postexilic, or Talmudic; and the post-Talmudic. The first rested on observation merely, the second on observation coupled with calculation, and the third on calculation only. In the first period the priests determined the beginning of each month by the appearance of the new moon and the recurrence of the prescribed feasts from the vernal and autumnal equinoxes. Thus, the month Abib (°abhibh), the first month of the year according to the Levitical law, in which the Passover was to be celebrated, was determined by observation (Ex 12:2; Deut 16:1).
(From International Standard Bible Encyclopaedia, Electronic Database Copyright © 1996, 2003, 2006 by Biblesoft, Inc. All rights reserved.)
An understanding of the calendar in biblical times is very important for serious biblical study. The calendar is used to organize and refer to those aspects of life that were important to the communities that used them. This is especially true of matters pertaining to the cult, more specifically worship. Moreover, an understanding of the systems by which the lives of ancient Israelites are organized introduces us more fully to the world views of the biblical period and thereby the influences that produced the Bible itself. . . .
All calendars used in the ancient Near East are dependent in some way on the movements of extraterrestrial bodies. While an agricultural year may be defined in terms of seasons and a liturgical year in terms of festivals, the overarching system, the rationale behind the nomenclature, is invariably connected to the movements of the sun, the moon, the stars, or some combination of these. Moreover, all ancient Near Eastern calendars presuppose a cycle, with the year the most fundamental cyclical unit. Though astronomical science certainly was not as highly developed as today, keen observation assured a regularity and uniformity of calendrical reckoning in the ancient Near East. . . .
The earliest references to methods of calendrical reckoning in ancient Israel (e.g., Ex 23:14-17; 34:18-26) demonstrate the influence of both lunar and solar phenomena. . . .
To the extent that Israel's historical experiences and perception of Yahweh acting in nature and history are different and special, Israel's calendar is unique. Israel's calendar therefore reflects both the common and the unique in both seasonal organization and the theological superstructure that provides its rationale. . . .
1. Year. The Israelite year was the most basic unit of the calendar. The individual components of the year might fluctuate, but all of these terms were inevitably linked to the conception of an annual cycle. Sometimes the year was a part of an even larger calendrical sequence, as in the notion of a Sabbatical Year (Ex 23:10; Lev 25:3-7; 1 Macc 6:49,53), a seven-year cycle, or the Jubilee Year (Lev 25:8; Num 36:4; Ezek 46:17; Isa 61:2 [Luke 4:19]), based on a forty-nine-year cycle. In general, however, the biblical calendrical terminology uses some singular form of the lunisolar year as the largest unit and calendrical references are made within this conceptual framework.
2. Month (yeraµ . . .). The two words commonly used to designate "month" in Hebrew both have lunar referents and etymologies. Yeraµ is derived from a root meaning "moon" (compare other Semitic languages where this root and its lunar referents are common). [It] may be used to refer to either the month proper (Ex 23:15; 34:18; Deut 16:11) or the day of the new moon (Num 28:11; Hos 2:13; Amos 8:5). Textual evidence seems to indicate that both words were used as a designation for month from an early period in the history of Israel, thus reflecting the lunar nature of the calendar. Also reflective of the lunar influence upon the calendar are the "new moon" days (Num 28:11; etc.), which were celebrated regularly and which designated the first day of each lunar month (Gen 38:24; Num 9:22; 11:20; Judg 11:37; 1 Sam 6:1; Amos 4:7; etc.). . . .
3. Week. The origin of the seven-day week is continually debated (cf., e.g., RSV and NEB on Gen 29:27). While reference to the week in the OT is relatively rare and confined primarily to cultic occasions (Ex 34:22; Lev 12:5; Num 28:26; Deut 16:9,16; etc.), the week appears to have been an important calendrical unit from an early period in Israel (Ex 34:22). The most important reference to the week-system is in conjunction with the feast of weeks
(µag . . .), indicating a cultic and agricultural source for its usage. Theories proposing that the week was derived originally from a lunar phase may be valid but have no supporting biblical evidence.
4. Sabbath. The sabbath, regardless of its origin, was a significant factor in the ancient Israelite calendrical system. Whether or however the sabbath and the week are to be related etiologically, by the time of the composition or Gen 1, the sabbath was considered the seventh day of the week (cf. also Ex 16:26; 20:10; 31:15; Lev 23:3; etc.). The important point to be noted here is the use of the sabbath as a punctuation mark for various events in the Israelite cultic calendar. The sabbath could mark the end of a weekly cycle (e.g., a rest/feast day, cf. Lev 23:3), a stopping-point from which calendrical reckoning could begin anew (Lev 23:15), or even a numerical collection of years. In any case, the sabbath and the seven-day cycle associated with it became the most important means of calendrical reference in Israel from the monarchical period onward.
5. Day (yōm). The day is the smallest, most consistent unit of the Hebrew calendar. Idioms using the Hebrew word for day often indicate longer periods of time (compilations of days). Though there is evidence that in early Christian times the day was divided into hours of quite specific and regular length (John 11:9; Matt 20:1-12), in general the primary divisions are morning and evening, day (light) and night (dark). There is evidence of calculation for the beginning of the day from both the rising of the sun (Gen 19:34) and its setting (Lev 23:27), though the latter appears to be the most common and the later development. The morning-evening distinction and division of Hebr. yom was often very important for the ritual instructions with calendrical notations (e.g., Num 28; Deut 16; etc.).
(From International Standard Bible Encyclopedia, revised edition, Copyright © 1979 by Wm. B. Eerdmans Publishing Co. All rights reserved.)
The WEEK - The week was a seven-day unit begun at the time of creation (Gen 1:31-2:2). The word week means "seven" (Gen 29:27; Luke 18:12). In the Bible the days of the week were called the "first day," "third day," and so forth (Gen 1:8-31; Matt 28:1), although the seventh day was known as "sabbath" (Ex 16:23; Matt 12:1). The day before the Sabbath was called "the Preparation Day" (Mark 15:42), and Christians referred to the first day of the week as "the Lord's Day" (Rev 1:10).
The MONTH - The month was a unit of time closely tied to the moon. The Hebrew word for "month" also meant "moon" (Deut 33:14, NIV, NASB). The reason for the connection between the month and the moon is that the beginning of a month was marked by a new moon. The moon was carefully observed by the people of Bible times. When it appeared as a thin crescent, it marked the beginning of a new month.
The lunar month was about 29 days long. Therefore, the first crescent of the new moon would appear 29 or 30 days after the previous new moon. At times the crescent was not visible because of clouds. But this was allowed for with a rule that the new moon would never be reckoned as more than 30 days after the last new moon. This prevented too much variation in the calendar. . . .
In the Old Testament - The marking of time in Old Testament days revolved primarily around the months, seasonal religious festivals, and the year. The month was marked by the first appearance of the crescent of the new moon at sunset. The first day of each month was considered a holy day marked by special sacrifices (Num 28:11-15), and it was to be announced with the blowing of trumpets (Num 10:10; Ps 81:3). . . .
In the New Testament - The New Testament contains no references to the Roman or Gentile calendar or to the Jewish calendar, except in speaking of the days of the week. There is also one reference to the "new moon" (Col 2:16). The Sabbath . . . is mentioned about 60 times (for instance, Matt 12:1-12). The New Testament also mentions the "first day," . . . (Mark 16:2; Luke 24:1; Acts 20:7; 1 Cor 16:2), "the Lord's Day," . . . (Rev 1:10), and the "Day of Preparation," or "Preparation Day," . . . (Matt 27:62; Mark 15:42; Luke 23:54; John 19:14,31,42). However, these are references to the cultic aspects of the Jewish calendar. Frequent mention is made, especially in the Gospel of John, of the Passover (John 2:13,23; 6:4; 11:55; 12:1; 13:1; 18:39). Other festivals mentioned in the New Testament are Unleavened Bread (Matt 26:17; Mark 14:1,12), Pentecost (Acts 2:1; 20:16; 1 Cor 16:8), Feast of Tabernacles (John 7:2), and the Feast of Dedication (John 10:22).
(From Nelson's Illustrated Bible Dictionary, Copyright © 1986, Thomas Nelson Publishers.)
(From McClintock and Strong Encyclopedia, Electronic Database. Copyright © 2000, 2003, 2005, 2006 by Biblesoft, Inc. All rights reserved.)