Bible Dictionary
CALENDAR
The biblical calendar was based chiefly on lunar months and regulated the seasons, civil activities, and religious festivals. Israel’s calendar developed from an early observational system into later systems that combined observation with calculation.
Biblical Usage
Israel’s calendar regulated the beginning of months, the Passover, other appointed feasts, Sabbatic observance, and civil activities. Abib was the first month for sacred purposes, while the year also had an older autumn reckoning for civil matters.