13 Thou shalt (ex)change the first engendered of an ass for a sheep, that if thou again-buyest it not, thou shalt slay it; forsooth thou shalt again-buy with price all the first begotten of a man of thy sons. (Thou shalt exchange the first-born of a donkey for a sheep, and if thou buyest it not back, then thou shalt kill it; but thou must buy back all thy first-born sons.)