Wherever Abram camps, there he builds an altar to the Lord. Earlier, when he comes to Canaan, God appears to him and confirms that the land he has come to is the one he is going to give to his descendants. Following this revelation, Abram builds an altar and calls on the name of the Lord (Genesis 12:7). Now also in Genesis 13:1–18 Abram builds an altar after God had appeared to him and confirmed his promise to him. So in all this, Abram, a godly man, seems to respond each time in a certain way to revelation from God. That response can be summed up in one word: worship. Abram kept his faith focused upon the God who had given him the promises.
18 So Abram moved his tent and came and settled by the oaks of Mamre, which are at Hebron, and there he built an altar to the LORD.