There he built an altar to the Lord

Genesis 12:8
And he moved from there to the mountain east of Bethel, and he pitched his tent with Bethel on the west and Ai on the east; there he built an altar to the Lord and called on the name of the Lord. 


The verse above occurred in Abraham's journey when he had arrived in Canaan. God had promised Abraham that the land of Canaan would belong to his descendants. This could be Abrahams's first arrival in the land of Canaan. Before this, God had called him out the city of Ur. The promises that God made to Abraham from the very beginning included:

Genesis 12
2 I will make you a great nation;
I will bless you
And make your name great;
And you shall be a blessing.
3 I will bless those who bless you,
And I will curse him who curses you;
And in you all the families of the earth shall be blessed.”


Just as Abraham followed God out of Ur, when God showed him the promised land and continued to lead him on, Abraham did not stay or procrastinate to go further. He was faithfully listening to God's direction. He did however built the altar before leaving Canaan, then built another altar near the mountain between Bethel and Canaan.

It does not give detailed motives for the altars but they could mean various things to Abraham. He could build it to mark God's promises to him to remind himself, he could have build in faith and declaring the land to be his in the future or he could be humbled by the favour of God and decided to mark the place where he prayed to God. In any case, he left physical symbols about his relationship with God.

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