1 Kings 3:4

4 The king went to Gibeon to offer sacrifices, for that was the most important high place, and Solomon offered a thousand burnt offerings on that altar.

Read 1 Kings 3:4 Using Other Translations

And the king went to Gibeon to sacrifice there; for that was the great high place: a thousand burnt offerings did Solomon offer upon that altar.
And the king went to Gibeon to sacrifice there, for that was the great high place. Solomon used to offer a thousand burnt offerings on that altar.
The most important of these places of worship was at Gibeon, so the king went there and sacrificed 1,000 burnt offerings.