And all Israel assembled themselves to king Solomon on the festival day in the month of Ethanim, the same is the seventh month.

and all the men of Israel are assembled unto king Solomon, in the month of Ethanim, in the festival, is the seventh month.

And all the men of Israel came together to King Solomon at the feast, in the month Ethanim, the seventh month.

And all of Israel assembled before king Solomon, on the solemn day in the month of Ethanim, which is the seventh month.

The feast in the month Ethanim - i. e. the Feast of Tabernacles, or the Feast of Ingathering, the commemoration of the dwelling in booths at the time of the Exodus (margin reference), and the festival of thanksgiving on account of the completion of harvest Exodus 23:16; Leviticus 23:39; Deuteronomy 16:13. It was one of the three on which the people were required to "appear before the Lord."

At the feast in the month Ethanim - The feast of tabernacles, which was celebrated in the seventh month of what is called the ecclesiastical gear.

And all the men of Israel assembled themselves unto king Solomon at the feast in the month (b) Ethanim, which [is] the seventh month.
(b) Containing part of September and part of October, in which they held three solemn feasts, (Numbers 29:1).

And all the men of Israel assembled themselves unto King Solomon at the feast,.... Not of tabernacles, as the Targum on 2-Chronicles 5:3 and so Jarchi; though that was in the same month next mentioned, and began on the fifteenth of it, and held seven days; wherefore this must be the feast of the dedication of the temple, and which was kept before that; since both lasted fourteen days, and the people were dismissed on the twenty third of the month; now not only the above principal persons convened, but a vast number of the common people came to see the solemnity of removing the ark, and of dedicating the temple, and to attend the feast of it, and the more, since in a few days was the time for all the males in Israel to appear there:
in the month Ethanim, which is the seventh month; it was, as the Targum says, originally the first month; but upon the children of Israel coming out of Egypt in Ab or Nisan, that became the first month, and this was the seventh from that; and is the same with Tisri, which answers to part of September, and part of October, here called Ethanim; which some render the month of the ancients, others of strong ones; either because of the many feasts that were in it, as some say; or because it was the time of ingathering all the increase and fruits of the earth, which strengthen and support man's life; or rather of "never failing", i.e. waters, showers falling in this month, and the rivers full of water (l); so September is "septimus imber", according to Isidore (m), and the three following months are alike derived; this, by the Egyptians, was called Theuth, and was with them the first month in the year (n); so Porphyry says (o), with the Egyptians the beginning of the year was not Aquarius, as with the Romans, but Cancer; and so the month of September was the first with the Ethiopians (p), and with most people (q); though with the Chinese about the middle of Aquarius (r). Now, though the temple was finished in the eighth month, 1-Kings 6:38, it was not dedicated until the seventh in the following year; it required time to finish the utensils and vessels, and put them in their proper place, and for the drying of the walls, &c.
(l) Vid. Hackman. Praecidan. Sacr. p. 130, 131. (m) Origin. l. 5. c. 33. (n) Lactant. de Fals. Felig. l. 1. c. 6. (o) De Antro Nymph. prope finem. (p) Ludolf. Lexic. Ethiopic. p. 65. & Hist. Ethiop. l. 3. c. 6. (q) Julian. Opera, par. 1. orat. 4. p. 290, 291. (r) Martin. Sinic. Hist. l. 1. p. 22.

THE DEDICATION OF THE TEMPLE. (1-Kings 8:1-12)
at the feast in the month Ethanim--The public and formal inauguration of this national place of worship did not take place till eleven months after the completion of the edifice. The delay, most probably, originated in Solomon's wish to choose the most fitting opportunity when there should be a general rendezvous of the people in Jerusalem (1-Kings 8:2); and that was not till the next year. That was a jubilee year, and he resolved on commencing the solemn ceremonial a few days before the feast of tabernacles, which was the most appropriate of all seasons. That annual festival had been instituted in commemoration of the Israelites dwelling in booths during their stay in the wilderness, as well as of the tabernacle, which was then erected, in which God promised to meet and dwell with His people, sanctifying it with His glory. As the tabernacle was to be superseded by the temple, there was admirable propriety in choosing the feast of tabernacles as the period for dedicating the new place of worship, and praying that the same distinguished privileges might be continued to it in the manifestation of the divine presence and glory. At the time appointed for the inauguration, the king issued orders for all the heads and representatives of the nation to repair to Jerusalem and take part in the august procession [1-Kings 8:1]. The lead was taken by the king and elders of the people, whose march must have been slow, as priests were stationed to offer an immense number of sacrifices at various points in the line of road through which the procession was to go. Then came the priests bearing the ark and the tabernacle--the old Mosaic tabernacle which was brought from Gibeon. Lastly, the Levites followed, carrying the vessels and ornaments belonging to the old, for lodgment in the new, house of the Lord. There was a slight deviation in this procedure from the order of march established in the wilderness (Numbers 3:31; Numbers 4:15); but the spirit of the arrangement was duly observed. The ark was deposited in the oracle; that is, the most holy place, under the wings of the cherubim--not the Mosaic cherubim, which were firmly attached to the ark (Exodus 37:7-8), but those made by Solomon, which were far larger and more expanded.

Accordingly "all the men of Israel (i.e., the heads of the tribes and families mentioned in 1-Kings 8:1) assembled together to the king in the month Ethanim, i.e., the seventh month, at the feast." Gesenius explains the name האתנים (in 55 codd. האיתנים) as meaning "month of the flowing brooks," after איתן in Proverbs 13:15; Bttcher, on the other hand, supposes it to denote the equinox. But apart from other grounds, the plural by no means favours this. Nor does the seventh month answer to the period between the middle of our September and the middle of October, as is supposed by Thenius, who founds upon this supposition the explanation already rejected by Bttcher, viz., "month of gifts;" but it corresponds to the period between the new moon of October and the new moon of November, during which the rainy season commences in Palestine (Rob. Pal. ii. p. 96ff.), so that this month may very well have received its name from the constant flowing of the brooks. The explanation, "that is the seventh month," is added, however (here as in 1-Kings 6:1, 1-Kings 6:38), not because the arrangement of the months was a different one before the captivity (Thenius), but because different names came into use for the months during the captivity. בּחג is construed with the article: "because the feast intended was one that was well known, and had already been kept for a long time (viz., the feast of tabernacles)." The article overthrows the explanation given by Thenius, who supposes that the reference is to the festivities connected with the dedication of the temple itself.

All Israel - Not only the chief men, but a vast number of the common people. The feast - The feast of the dedication, to which Solomon had invited them. Seventh month - Which time he chose with respect to his peoples convenience, because now they had gathered in all their fruits, and were come up to Jerusalem, to celebrate the feast of tabernacles. But the temple was not finished till the eighth month, 1-Kings 6:38, how then could he invite them in the seventh month? This was the seventh month of the next year. For although the house in all its parts was finished the year before, yet the utensils of it were not then fully finished: and many preparations were to be made for this great and extraordinary occasion.