John Calvin Commentary Haggai 1:15

"in the four and twentieth day of the month, in the sixth [month], in the second year of Darius the king." — Haggai 1:15 (ASV)

The Prophet even mentions the time when they began building the temple. Twenty-three days passed between the first message and the beginning of the work. From this it appears how ignorant the one who divided the chapters was, having begun the second chapter at this verse, where the Prophet shows, as it were by his finger, how great the distance was between the day on which he began to exhort the people and the success he speaks of.

He then simply tells us here when the Temple began to be built—that is, in the second year of Darius the king, and on the twenty-fourth day of the sixth month. He had previously said that a message was given to him in the second year of Darius the king, and in the sixth month, and on the first day.

Then from that day until the twenty-fourth, the people delayed; it was not that they disregarded the Prophet's command, but because it was not so easy to persuade them all to unanimously undertake the work. Although the people's promptness is commended, we must still observe that there was some mixture of weakness, for the effect of the doctrine did not appear until the twenty-fourth day. It afterwards follows—