Neither say they in their heart, Let us now fear the LORD our God, that giveth rain, both the former and the latter, in his season: he reserveth unto us the appointed weeks of the harvest. Giveth rain, both the former and the latter - See the note on Jeremiah 3:3.
The appointed weeks of the harvest - As the early rains fell in the northern parts of Judea about the end of September, in the civil year of the Hebrews, so the latter rains fell before harvest, in the months of March and April. The appointed weeks of the harvest were those which fell between the passover and pentecost. In the southern parts the harvest was earlier than in the northern. Dr. Blayney translates, "A sufficiency of the appointed things of harvest he secureth to us."
If the word שבעת weeks, be read with a ש sin instead of a ש shin, it will signify fullness or sufficiency; and thus the Septuagint and Vulgate have read it. I think the present reading is much to be preferred. God appoints a harvest time, and in his good providence he generally gives harvest weather.