NOTES for Gen 13:1-18
A moment comes when Abraham remains alone, having separated even from his nephew Lot, with whom he had wandered for quite a long time. It is then, when this has happened, that God addresses Abraham, reminding him of the promises given back in Haran concerning the future of the land to which Abraham has come and the destiny of his descendants, who are to take possession of it.
Why not earlier? Why not when Abraham and Lot were still walking together? The answer to the question may be the choice Lot made about the place of his future residence. Abraham, as is not hard to notice, keeps away from large cities. If he is ever in them, it is only when he has no other option, for example when he has to survive dry and therefore barren years. Then there is nowhere else to go, and Abraham seeks refuge in cities. In general, however, he tries to stay away from cities for a whole range of reasons, both political and spiritual. Life in a city is in some ways easier, but there are more temptations there too. It is comparatively easy to assimilate there, but then Abraham would have had to give up following his God, the One who had called Abraham after Himself.
Abraham did not know everything about his God, but he knew enough to understand that he needed both political and spiritual independence in order to remain faithful to his God. Lot looks at things differently. He likes the land near Sodom, and he is ready to go where the land is good, even if the people there are evil. This is his essential difference from Abraham, and therefore God does not reveal His plans to Lot. God is silent until Lot has made his choice, until he has gone where his own heart leads him, the heart that liked the land of Sodom. But when Lot leaves, God reveals to Abraham the future of his descendants, for Abraham too has made his choice, remaining where God led him from the beginning and not trying to look for better, more comfortable places to live. God does not keep each person from choosing his own, but He leads only the one who chooses His way, as Abraham chose that way.