'Built an Altar' in the Bible

Then Joshua built an altar to the Lord, the God of Israel, on Mount Ebal,

And the [other] sons of Israel heard it said, “Look, the sons of Reuben and the sons of Gad and the half-tribe of Manasseh have built an altar at the edge of the land of Canaan, in the region [west] of the Jordan, on the side belonging to the sons of Israel.”