Exodus 12:2
This month shall be to you the beginning of months: it shall be the first month of the year to you.
Nave's Topical Index—AKJV

Numbers 10:10
Also in the day of your gladness, and in your solemn days, and in the beginnings of your months, you shall blow with the trumpets over your burnt offerings, and over the sacrifices of your peace offerings; that they may be to you for a memorial before your God: I am the LORD your God.
Nave's Topical Index—AKJV

Numbers 28:11
And in the beginnings of your months you shall offer a burnt offering to the LORD; two young bullocks, and one ram, seven lambs of the first year without spot;
Nave's Topical Index—AKJV