If the man have no kinsman, which might be the case commonly with proselytes, if not with Israelites. This also suppposeth the person injured to be dead or gone away into some unknown place, and the person injured to be known to the injurer. God appointed the priest as his deputy to receive his dues, and take them to his own use, that so he might more cheerfully and entirely devote himself to the ministration of holy things. This is au additional explication to that law, Leviticus 6:2, and for the sake thereof it seems here to be repeated.
Related Commentaries of Numbers 5:8
Numbers 5:8
8 But if the man have no kinsman to recompense the trespass unto, let the trespass be recompensed unto the LORD, even to the priest; beside the ram of the atonement, whereby an atonement shall be made for him.