Bilangan 18:15

18:15 The firstborn of every womb which they present to the Lord, whether human or animal, will be yours. Nevertheless, the firstborn sons you must redeem, ¹  and the firstborn males of unclean animals you must redeem.

Bilangan 29:8

29:8 But you must offer a burnt offering as a pleasing aroma to the Lord, one young bull, one ram, and seven lambs one year old, all of them without blemish. ² 

Bilangan 31:19

Purification After Battle

31:19 “Any of you who has killed anyone or touched any of the dead, remain outside the camp for seven days; purify yourselves and your captives on the third day, and on the seventh day.

[18:15]  ¹ tn The construction uses the infinitive absolute and the imperfect tense of the verb “to redeem” in order to stress the point – they were to be redeemed. N. H. Snaith suggests that the verb means to get by payment what was not originally yours, whereas the other root גָאַל (ga’al) means to get back what was originally yours (Leviticus and Numbers [NCB], 268).

[29:8]  ² tn Heb “they shall be to you without blemish.”