2 Chronicles 8:12

Then Solomon offered burnt offerings unto the LORD on the altar of the LORD, which he had built before the porch,

The verse belongs to the account of Solomon's reign that gives special attention to the building and dedication of the temple and its services. In that setting sacrifices are part of the temple service. Their place in the history shows the religious importance of temple worship in it.

The verse shows Solomon himself offering burnt offerings unto the Lord on the altar of the Lord which he had built before the porch. Taken together with the next verse, it shows he continued these priestly duties on Sabbaths and at the annual feasts, burning sacrifices and offering incense. Thereby he united the offices of king and priest in his own person after the example of David.