Exodus 34:19
"All that openeth the matrix is mine; and every firstling among thy cattle, whether ox or sheep, that is male."
Cross References (ranked by relevance)
Sanctify unto me all the firstborn, whatsoever openeth the womb among the children of Israel, both of man and of beast: it is mine.
Thou shalt not delay to offer the first of thy ripe fruits, and of thy liquors: the firstborn of thy sons shalt thou give unto me.
That thou shalt set apart unto the LORD all that openeth the matrix, and every firstling that cometh of a beast which thou hast; the males shall be the LORD’s.
And the first of all the firstfruits of all things, and every oblation of all, of every sort of your oblations, shall be the priest’s: ye shall also give unto the priest the first of your dough, that he may cause the blessing to rest in thine house.
(As it is written in the law of the LORD, Every male that openeth the womb shall be called holy to the Lord;)