Genesis 12:8

And he removed from thence, broke up his encampment, and went unto a mountain on the east of Bethel, and pitched his tent, having Bethel on the west and Hai on the east; and there he builded an altar unto the Lord, and called upon the name of the Lord. The geographical notation in many cases is that of the later age, in which the author lived, for the sake of a quicker understanding. Abram's new encampment was in the hill country of what was afterwards Ephraim, between Ai on the west and Lus, or Bethel, on the east. Here again he inaugurated the worship of the true God by preaching and prayer, for he felt responsible for his whole household and therefore taught also his slaves and house-servants the way of salvation.