Charles Ellicott Commentary 1 Kings 9:25

"And three times a year did Solomon offer burnt-offerings and peace-offerings upon the altar which he built unto Jehovah, burning incense therewith, [upon the altar] that was before Jehovah. So he finished the house." — 1 Kings 9:25 (ASV)

And three times in a year. —This verse seems, by its last words, to be a kind of note or postscript to the description of the completion and consecration of the Temple. To the record of the great inaugural sacrifice it adds a notice of the solemn renewal of the royal offering, both of victims and of incense, three times in a year—no doubt at the three great feasts, the Passover, the Feast of Weeks, and the Feast of Tabernacles. As has been already said (see Note on 1 Kings 8:63), there is no reason to suppose that on these occasions, or on any others, Solomon personally usurped the priest's office.