However, the people were sacrificing on the high places, because until that time a temple for the Lord's name had not been built.
1 Kings 3:2 In-Context
Solomon made an alliance with Pharaoh king of Egypt and married his daughter. He brought her to the City of David until he finished building his palace and the temple of the LORD, and the wall around Jerusalem.
The people, however, were still sacrificing at the high places, because a temple had not yet been built for the Name of the LORD.
Solomon showed his love for the LORD by walking according to the instructions given him by his father David, except that he offered sacrifices and burned incense on the high places.
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.
At Gibeon the LORD appeared to Solomon during the night in a dream, and God said, “Ask for whatever you want me to give you.”