NOTES for Gen 12:1-20
Abraham's story begins simply: he heard the voice of God and followed an unknown God. There are quite a few clever comments, both Jewish and Christian, about Abraham's spiritual searching before this first encounter with God. In the Bible, however, nothing is said about such searches. The better answer is that there were none: Abraham simply managed to trust the unknown God. Why? We will hardly find an answer to that question today. The point, of course, is not the voice itself as such, and not even the promises God gives Abraham.
To hear the voice of a god or a spirit in those days was not at all rare; many people heard voices, and rather often. True, usually these were the voices of known and familiar gods and spirits, and they said something that fit easily into the life context of the one to whom the voice was addressed. With Abraham it was different: the voice belonged to someone Abraham did not know, and it promised something he could not have expected. He was already over seventy, far from the age when, according to the established ideas of that time, one could begin something serious and set out on a dangerous journey. And who was this unknown one calling him after himself? He promises much, but will he fulfill it? There was only one way to find out: go and see. Or not go and not see. Abraham chooses the first, though he did not have to take the risk. Why he chooses what he chose remains the mystery of his heart. One thing is clear: this choice determined the destiny of the people of God and began their history.
Sometimes people ask: could Abraham have refused, not gone after the God unknown to him? What would have happened then? Of course he could have: the human person is free, and God does not encroach on his freedom. Then God would have had to look for someone else, and there is no doubt that He would have found such a person. Only it would already have been a different history of a different people. Abraham said "yes" to God, and the history of the people of God became what we know from the Bible.