Because he hath sinned, and is guilty. This guilt of his being manifested, either by his refusing to swear when called to it, as in some of the cases alleged; or by his voluntary confession upon remorse, whereby he reapeth this benefit, that he only restores the principal with the addition of a fifth part; whereas if he were convicted of his fault, he was to pay double, Exodus 22:9.
Related Commentaries of Leviticus 6:4
Leviticus 6:4
4 Then it shall be, because he hath sinned, and is guilty, that he shall restore that which he took violently away, or the thing which he hath deceitfully gotten, or that which was delivered him to keep, or the lost thing which he found,