on why Abraham was chosen by God, based on Joshua 24:2-3.
And Joshua said unto all the people, Thus saith the LORD God of Israel, Your fathers dwelt on the other side of the flood in old time, even Terah, the father of Abraham, and the father of Nachor: and they served other gods. And I took your father Abraham from the other side of the flood, and led him throughout all the land of Canaan, and multiplied his seed, and gave him Isaac.
writers of midrash had so much fun...
Terah, the father of Abraham and Haran, was a dealer in images as well as a worshipper of them. Once when he was away he gave Abraham his stock of graven images to sell in his absence. In the course of the day an elderly man came to make a purchase. Abraham asked him his age, and the man gave it as between fifty and sixty years. Abraham taunted him with want of sound sense in calling the work of another man's hand, produced perhaps in a few hours, his god; the man laid the words of Abraham to heart and gave up idol worship. Again a woman came with a handful of fine flour to offer to Terah's idols, which were now in charge of Abraham. He took a stick and broke all the images except the largest one, in the hand of which he placed the stick which had worked this wholesale destruction. When his father returned and saw the havoc committed on his 'gods' and property he demanded an explanation from his son whom he had left in charge. Abraham mockingly explained that when an offering of fine flour was brought to these divinities they quarrelled with each other as to who should be the recipient, when at last the biggest of them, being angry at the altercation, took up a stick to chastise the offenders, and in so doing broke them all up. Terah, so far from being satisfied with this explanation, understood it as a piece of mockery, and when he learnt also of the customers whom Abraham had lost him during his management he became very incensed, and drove Abraham out of his house and handed him over to Nimrod.
Nimrod suggested to Abraham that since he had refused to worship his father's idols because of their want of power, he should worship fire, which is very powerful: Abraham pointed out that water has power over fire. 'Well,' said Nimrod, 'let us declare water god.' 'But,' replied Abraham,' the clouds absorb the water and even they are dispersed by the wind.' 'Then let us declare the wind our god.' 'Bear in mind,' continued Abraham, 'that man is stronger than wind, and can resist it and stand against it.' Nimrod, becoming weary of arguing with Abraham, decided to cast him before his god -- fire -- and challenged Abraham's deliverance by the God of Abraham, but God saved him out of the fiery furnace. Haran too was challenged to declare his god, but halted between two opinions, and delayed his answer until he saw the result of Abraham's fate. When he saw the latter saved he declared himself on the side of Abraham's God, thinking that he too, having now become an adherent of that God, would be saved by the same miracle. But since his faith was not real, but depended on a miracle, he perished in the fire, into which like Abraham he was cast by Nimrod. This is hinted in the words (Gen. 11:28): 'And Haran died before his father Terah in the land of his nativity, in Ur of the Chaldees.'
