51 If many years remain, they must pay for their redemption a larger share of the price paid for them.

Read Leviticus 25:51 Using Other Translations

If there be yet many years behind, according unto them he shall give again the price of his redemption out of the money that he was bought for.
If there are still many years left, he shall pay proportionately for his redemption some of his sale price.
If many years still remain until the jubilee, they will repay the proper proportion of what they received when they sold themselves.