Exodus 13:9

6 Seven days thou shalt eat unleavened bread, and in the seventh day shall be a feast to Jehovah.

7 Unleavened bread shall be eaten throughout the seven days; and there shall no leavened bread be seen with thee, neither shall there be leaven seen with thee, in all thy borders.

8 And thou shalt tell thy son in that day, saying, It is because of that which Jehovah did for me when I came forth out of Egypt.

9 And it shall be for a sign unto thee upon thy hand, and for a memorial between thine eyes, that the law of Jehovah may be in thy mouth: for with a strong hand hath Jehovah brought thee out of Egypt.

10 Thou shalt therefore keep this ordinance in its season from year to year.

11 And it shall be, when Jehovah shall bring thee into the land of the Canaanite, as he sware unto thee and to thy fathers, and shall give it thee,

12 that thou shalt set apart unto Jehovah all that openeth the womb, and every firstling which thou hast that cometh of a beast; the males shall be Jehovah`s.