Deuteronomy 12:14

and has not brought it to the doorway of the tent of meeting to bring it near as an offering to Yahweh before the tabernacle of Yahweh, it will be counted as bloodguiltiness to that man. He has shed blood, and that man shall be cut off from among his people.

“Far be it from us to rebel against Yahweh and turn away from following Yahweh this day, by building an altar for burnt offering, for grain offering or for sacrifice, besides the altar of Yahweh our God which is before His tabernacle.”

So Saul said, “Bring near to me the burnt offering and the peace offerings.” And he offered the burnt offering.

The people were still sacrificing on the high places because there was no house built for the name of Yahweh until those days.

“If this people go up to offer sacrifices in the house of Yahweh at Jerusalem, then the heart of this people will return to their lord, even to Rehoboam king of Judah; and they will kill me and return to Rehoboam king of Judah.”