The Lord stirred up the two leaders and the people to resume work on the temple (cf. 2 Chronicles 36:22-23; Ezra 1:5). Work began again on the twenty-fourth day of that very month. Perhaps it took three weeks for the people to make their decision and make preparations, including cutting wood (cf. Haggai 1:8). There was also a harvest of figs, grapes, and pomegranates in the month of Elul, which may also have delayed them. [1][source]
"God is not portrayed here as a divine puppeteer who manipulates people, but as a sovereign king who rewards obedience by giving it a boost." [2][source]