Erchin, 25a: It implies that, when redeeming the field, the owner must pay the full amount up-front, and not in annual instalments. ¹

Sifra: It implies that the owner can onlyt redeem his field at least two years before the Yocel and at least two years after the Yovel.

Erchin,25a: It means that he deducts he deducts from the sum that he has to pay Hekdesh what he ate, from the Yovel until the time that he redeems the field - including whatever Hekdesh ate - and even if Hekdesh, for some reason, did not eat from the field. ¹