The Hebrew calendar (הלוח העברי ha'luach ha'ivri), or Jewish calendar, is a lunisolar calendar used today predominantly for Jewish religious observances. It determines the dates for Jewish holidays and the appropriate public reading of Torah portions, yahrzeits (dates to commemorate the death of a relative), and daily Psalm reading, among many ceremonial uses. In Israel, it is an official calendar for civil purposes and provides a time frame for agriculture.

Originally the Hebrew calendar was used by Jews for all daily purposes, but following the conquest of Jerusalem by Pompey in 63 BCE (see also Iudaea province), Jews began additionally following the imperial civil calendar, which was decreed in 45 BCE, for civic matters such as the payment of taxes and dealings with government officials.

The Hebrew calendar has evolved over time. For example, until the Tannaitic period, the months were set by observation of a new crescent moon, with an additional month added every two or three years to keep Passover in the spring, again based on observation of natural events, namely the ripening of the barley crop, the age of the kids lambs and doves, the ripeness of the fruit trees, and the relation to the Tekufah (seasons.) Through the Amoraic period and into the Geonic period, this system was displaced by mathematical rules. The principles and rules appear to have been settled by the time Maimonides compiled the Mishneh Torah in the 12th century.

Jacob's Trouble was an American, Christian, rock band formed in Atlanta, Georgia area in the 1980s. The group originally consisted of members Jerry Davison (drums), Mark Blackburn (guitar), and Steve Atwell (bass), with Davison and Blackburn handling the lead vocals.

In 1989, Jacob's Trouble released their debut Terry Taylor-produced album, The Door Into Summer, a mixture of original numbers and cover versions of songs by The Beatles and The Monkees.

A year later the band released their second album, Knock, Breathe, Shine. The band received notice at the time for the song "About Sex", a song about the proper role of sex in society from a Christian perspective. Fearing a fundamentalist label, the band opted to remove the song from the album and replaced it with the more ambiguous "About Sex, Part 2".^{[citation needed]} Despite this, the album was the group's best-selling record. They performed "About Sex" during a concert at Dellinger Park in Cartersville, GA.

One of Jacob's Trouble's songs, These Thousand Hills, was given much wider exposure when Third Day performed a cover of the song on their album Offerings. Jacob's Trouble was referred to as "being a band ahead of its time."