Exodus 12:2, This month…first month of the year. The biblical month in which Passover occurs (March-April) marks the beginning of the biblical new year. It is also the time from which all biblical feasts are calculated. This is why it is important to understand the biblical calendar, so you will know when to celebrate YHVH’s feasts.
To learn about the ancient biblical calendar, we provide these free resources for you to study:
The Biblical Calendar and the New Moon at http://www.hoshanarabbah.org/pdfs/new_moons.pdf
The Biblical Calendar Demystified at http://www.hoshanarabbah.org/pdfs/cal_demyst.pdf
The Biblical Calendar: New Moon or Conjunction?