Leviticus 27:20

20. If he will not redeem Since the priests were employed in the sanctuary and could not secularize themselves by cultivating patches of land scattered through the country, the land vowed lay idle or was still cultivated by its proprietor. As a penalty for his neglect to pay the redemption year by year, the land was forfeited to the sanctuary in the jubilee. “Hence it is to be inferred that a consecrated field must have been redeemed before the jubilee unless any one manifestly wished it to be alienated.” Clericus.

If he have sold Knobel thinks that only culpable caprice or dishonesty could have induced the proprietor to sell a field after he had vowed it to the Lord. The fact that it became irredeemable after such an act seems to favour this theory. The fault, for which the forfeiture of the field is a penalty, may have consisted in the fact that he still assumed undisputed ownership of a field which he had solemnly consecrated to the Lord, to whose rights he had done violence by the sale.