The feast of harvest. Fifty days were to be numbered from the day of offering the barley sheaf, and on the fiftieth the feast of harvest, thence called "Pentecost," was to be celebrated. Different Jewish sects make different calculations; but the majority celebrate Pentecost on the sixth of Sivan. The main ceremony was the offering to God of two leavened loaves of the finest flour made out of the wheat just gathered in, and called the first-fruits of the harvest. The festival lasted only a single day; but it was one of a peculiarly social and joyful character (Deuteronomy 16:9-11). Jewish tradition connects the feast further with the giving of the law, which must certainly have taken place about the time (see Exodus 19:1-16). The firstfruits. Rather, "Of the first-fruits." The word is in apposition with "harvest," not with "feast." Which thou hast sown. The sown harvest was gathered in by Pentecost; what remained to collect afterwards was the produce of plantations.
The feast of ingathering. Called elsewhere, and more commonly, "the feast of tabernacles" (Le 23:34; Deuteronomy 16:13; Deuteronomy 31:10; John 7:2), from the circumstance that the people were commanded to make themselves booths, and dwell in them during the time of the feast. The festival began on the 15th of Tisri, or in the early part of our October, when the olives had been gathered in and the vintage was completed. It lasted seven, or (according to some) eight days, and comprised two holy convocations. In one point of view it was a festival of thanksgiving for the final getting in of the crops; in another, a commemoration of the safe passage through the desert from Egypt to Palestine. The feast seems to have been neglected during the captivity, but was celebrated with much glee in the time of Nehemiah (Nehemiah 8:17). In the end of the year—i.e; the end of the agricultural year—when the harvest was over—as explained in the following clause.