built an altar
Genesis 8:20
Then Noah built an altar to the LORD, and took of every clean animal and of every clean bird, and offered burnt offerings on the altar.
Genesis 12:7
Then the LORD appeared to Abram, and said, "To your descendants I will give this land." So he built there an altar to the LORD, who had appeared to him.
Genesis 12:8
Thence he removed to the mountain on the east of Bethel, and pitched his tent, with Bethel on the west and Ai on the east; and there he built an altar to the LORD and called on the name of the LORD.