פֿאַרבונדענע פּסוקים אויף שמות 34:21

Rebbi Aḥa in the name of Rebbi Joḥanan: When they forbade it, they were inspired by Scripture¹⁰It is not claimed that the rules of the Sabbatical year in the Second Commonwealth are biblical, only that they are inspired by the interpretation of biblical verses., and when they permitted it, they were inspired by Scripture. When they forbade it, they were inspired by Scripture, (Lev. 25:3): “You shall rest from ploughing and harvesting,” from ploughing when harvesting is forbidden; what is this? This is ploughing in the year preceding the Sabbatical in preparation of the Sabbatical. And from harvesting when ploughing is forbidden, what is this? That is the harvest of Sabbatical growth after the Sabbatical. When they permitted it, they were inspired by Scripture, (Ex. 20:9): “Six days you shall labor and do all your work,” just as on the eve of the Sabbath of Creation³The Sabbath day. one may do work until sundown, also before the start of the Sabbatical year one may work until sundown¹¹Sundown of the eve of New Year’s Day.
The Babli (Mo‘ed qaṭan 3b–4a) has another interpretation, based on R. Ismael’s opinion in Mishnah 1:5. It cannot accept the interpretation here since in the theory of the Babli one is obliged by biblical decree to start Sabbath and holidays some time before sundown (Yoma 82b, Roš Haššanah 9a)..