1 Kings 18:30-32

18:30 Elijah then told all the people, “Approach me.” So all the people approached him. He repaired the altar of the Lord that had been torn down. 18:31 Then Elijah took twelve stones, corresponding to the number of tribes that descended from Jacob, to whom the Lord had said, “Israel will be your new name.” 18:32 With the stones he constructed an altar for the Lord. Around the altar he made a trench large enough to contain two seahs of seed.