'Know that I Am the Lord' in the Bible

A prophet came to Ahab king of Israel and said, “This is what the Lord says: ‘Do you see this entire great army? Watch, I am handing it over to you today so that you may know that I am Yahweh.’”

Then the man of God approached and said to the king of Israel, “This is what the Lord says: ‘Because the Arameans have said: Yahweh is a god of the mountains and not a god of the valleys, I will hand over all this great army to you. Then you will know that I am the Lord.’”