John Calvin on Deuteronomy 16:13-15

13. Thou shalt observe the feast of tabernacles. Its first day was called the day of In-gathering, (collectionum,) because the produce of the whole year was then stored in their granaries “Aux greniers, ou aux caves, ou fenils, et gardoirs de toute provision.” — Fr. and provision cellars. Since, therefore, they then rested from their rural labors, it was a convenient time of year for the celebration of the festivals; for in order that they might more willingly go up to Jerusalem, it was arranged by God, that it should be done with but little expense and sacrifice of their domestic interests. Where our translation is, “When Jehovah shall have blessed thee,” it stands literally, “Because he shall bless thee,” Vide A. V., ver. 15, “Because the Lord thy God shall bless thee,” etc. but the sense is nearly the same; for Moses assures them that, provided they devote their minds diligently and faithfully to the service of God, they shall never want grounds for rejoicing, since He will never interrupt the flow of His blessing. The end, therefore, of the fifteenth verse, is not a mere command, but also a promise; as if he had said, that, if they were not ungrateful, there was no fear but that God would continually supply new cause for gladness; and these two clauses are to be taken in connection, “God will bless thee, and, therefore, thou shalt only rejoice;” for in this passage I willingly interpret thus “Car il y a ici un mot qui se prend bien pour Toutes fois; mais il signifie pareillement Tant y a, ou Quoy qu’il en soit, ou Pour vrai;” for there is here a word, which may properly mean, Nevertheless; but it also means However, or, At any rate, or, Truly. — Fr.

"Only (Utique, Vatablus; veruntamen, Pagninus; profrcto, Malvenda) joyful; understand, and not sad, i.e., You shall indulge in nothing but rejoicing.” — Pol. Syn. in loco. the particle אך, ak. It is indeed absurd to take it adversatively. It will not, therefore, be improper to explain it exclusively, as if he said, that, there should be no sorrow or anxiety, which should hinder them from the performance of their pious duty; those who render it “surely,” approach also to this meaning.