After much consideration I have concluded the answer is obvious. A person blind in one eye and can't see out of the other one can answer this question. Therefore, go find a person that is blind in one eye and can't see out of the other for the answer. :)

Let me give it a try. Genesis 12 simply states that God spoke to Abraham. I tried finding a reason, but could not in that passage. This got me to thinking about other people God singled out for His purposes. In Romans 9 we read of God loving Jacob and hating Esau in verse 13. Backing up to verse 11 we see that this was said before either one was born. In verse 14 the question is raised "Is there unrighteousness with God?" and the answer, "Certainly not!" The point Paul is making is that God's selection was based on His mercy and compassion. The Jews accepted God’s choosing of Jacob over Esau without impugning Him with evil or prejudice.

In Jeremiah, God said, "Before I formed you in the womb I knew you; before you were born I sanctified you; I ordained you a prophet to the nations" Jeremiah 1.5. While God chooses whomever He wishes, we know that God is omniscience. He knew Pharaoh would reject Moses' charge to let the children of Israel go; He knew that Israel would become unfaithful after the days of Joshua. Therefore, I believe God knew the heart and character of Abraham before He called him out of his homeland. One passage that says a lot to me about Abraham's character and God's view of Abraham is Geneis 18.19. "For I have known him, in order that he may command his children and his household after him, that they keep the way of the Lord, to do righteousness and justice, that the Lord may bring to Abraham what He has spoken to him." The Lord knew that Abraham would command his household to keep the commandment of God.

Let me know if you come up with some thing better or more or if you think I am all wet. Or if you find the man blind in one eye and can't see out of the other.