Leviticus 27:27
and shall add: 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 it. Lev 27:11-13 Reciprocal: Lev 5:16 - the fifth Num 18:15 - the firstborn Neh 10:36 - the firstborn