1 Kings 8:2

The month Ethanim. The month is given but not the year. Many believe that it was the year after the completion of the Temple. Since the Temple was completed in the month Bui, the 8th month (1 Kings 6:38), and since the dedication took place in Ethanim, the 7th month, this would be 11 months after the Temple was finished. Others hold that the dedication did not take place till some years later, perhaps a year of jubilee, or the 24th year of King Solomon’s reign — 13 years after the completion of the Temple (1 Kings 7:1).

After the Exile the 7th month was called Tishri, from the Akkadian or early Babylonian Tashritu, “beginning.” The name implies a calendar beginning with this month. The civil year of the united monarchy and the kingdom of Judah began with Tishri. The first of that month was a day of holy convocation (Num. 29:1), the beginning of the new year. On the 10th day of that month was the solemn Day of Atonement when the cleansing of the sanctuary took place (Num. 29:7; Lev. 16:29, 30; 23:27), and on the 15th day began the Feast of Tabernacles (Num. 29:12; Lev. 23:34; Deut. 16:13; Neh. 8:14-18; Eze. 45:25). The beginning of this month corresponded approximately with the new moon of September or October.