The city which claims the distinction of being Abraham's birthplace, or at least of giving its name to the district where he was born, is now represented by a few mounds of ruins rising out of the flat marshy ground on the western bank of the Euphrates, not far above the point where it joins its waters to those of the Tigris and glides on to the Persian gulf. In the time of Abraham, Ur was the capital city which gave its name to one of the most populous and fertile regions of the earth. The whole land of Accad which ran up from the sea-coast to Upper Mesopotamia (or Shinar) seems to have been known as Ur-ma, the land of Ur. This land was of no great extent, being little if at all larger than Scotland, but it was the richest of Asia. The high civilisation which this land enjoyed even in the time of Abraham has been disclosed in the abundant and multifarious Babylonian remains which have recently been brought to light.
What induced Terah to abandon so prosperous a land can only be conjectured. It is possible that the idolatrous customs of the inhabitants may have had something to do with his movements. For while the ancient Babylonian records reveal a civilisation surprisingly advanced, and a social order in some respects admirable, they also make disclosures regarding the worship of the gods which must shock even those who are familiar with the immoralities frequently fostered by heathen religions. The city of Ur was not only the capital, it was the holy city of the Chaldeans. In its northern quarter rose high above the surrounding buildings the successive stages of the temple of the moon-god, culminating in a platform on which the priests could both accurately observe the motions of the stars and hold their night-watches in honour of their god. In the courts of this temple might be heard breaking the silence of midnight, one of those magnificent hymns, still preserved, in which idolatry is seen in its most attractive dress, and in which the Lord of Ur is invoked in terms not unworthy of the living God. But in these same temple-courts Abraham may have seen the firstborn led to the altar, the fruit of the body sacrificed to atone for the sin of the soul; and here too he must have seen other sights even more shocking and repulsive. Here he was no doubt taught that strangely mixed religion which clung for generations to some members of his family. Certainly he was taught in common with the whole community to rest on the seventh day; as he was trained to look to the stars with reverence and to the moon as something more than the light which was set to rule the night.
Possibly then Terah may have been induced to move northwards by a desire to shake himself free from customs he disapproved. The Hebrews themselves seem always to have considered that his migration had a religious motive. "This people," says one of their old writings, "is descended from the Chaldeans, and they sojourned heretofore in Mesopotamia because they would not follow the gods of their fathers which were in the land of Chaldea. For they left the way of their ancestors and worshipped the God of heaven, the God whom they knew; so they cast them out from the face of their gods, and they fled into Mesopotamia and sojourned there many days. Then their God commanded them to depart from the place where they sojourned and to go into the land of Canaan." But if this is a true account of the origin of the movement northwards, it must have been Abraham rather than his father who was the moving spirit of it; for it is certainly Abraham and not Terah who stands as the significant figure inaugurating the new era.
If doubt rests on the moving cause of the migration from Ur, none rests on that which prompted Abraham to leave Charran and journey towards Canaan. He did so in obedience to what he believed to be a Divine command, and in faith on what he understood to be a Divine promise. How he became aware that a Divine command thus lay upon him we do not know. Nothing could persuade him that he was not commanded. Day by day he heard in his soul what he recognised as a Divine voice, saying: "Get thee out of thy country and from thy kindred and from thy father's house, unto a land that I will show thee!" This was God's first revelation of Himself to Abraham. Up to this time Abraham to all appearance had no knowledge of any God but the deities worshipped by his fathers in Chaldea. Now, he finds within himself impulses which he cannot resist and which he is conscious he ought not to resist. He believes it to be his duty to adopt a course which may look foolish and which he can justify only by saying that his conscience bids him. He recognises, apparently for the first time, that through his conscience there speaks to him a God Who is supreme. In dependence on this God he gathered his possessions together and departed.