Leviticus 27:13

Verse Leviticus 27:13. Shall add a fifth part] This was probably intended to prevent rash vows and covetous redemptions. The priest alone was to value the thing; and to whatever his valuation was, a fifth part must be added by him who wished to redeem the consecrated thing. Thus, if the priest valued it at forty shekels, if the former owner redeemed it he was obliged to give forty-eight.