Abraham asked the question that every prophet and mystic after him would ask: "O Eternal, Mighty One! Why have you established that things should be this way, and then proclaimed the knowledge of it?"
Why create a world where evil exists, and then announce in advance that it will exist? Why not simply prevent it?
God did not answer with theology. He answered with a question of His own.
"Hear, Abraham. Understand what I say to you, and answer me as I question you. Why did your father Terah not listen to your voice? Why did he not cease from his devilish idolatry until he perished, along with his whole household?"
Abraham answered honestly: "Entirely because he chose not to listen to me. But I, too, did not follow his works."
God pressed the point home: "As the counsel of your father is in him, and as your counsel is in you, so also is the counsel of my will in me, ready for the coming days, before you have knowledge of them or can see with your eyes what is future in them."
The argument was elegant. Terah had free will. He chose idols. Abraham had free will. He chose God. Father and son, given the same world, made opposite choices. From these two contrary examples, God justified His own freedom to permit evil. If human will is genuinely free, then God must allow it to choose wrongly. The alternative is no freedom at all.
"How those of your seed will be," God said, "look in the picture."
The vision that followed would show Abraham the cost of that freedom.