Shall Not the Judge of All the Earth Do Right? (Genesis 18)

Shall I hide from Abraham what I am doing, since Abraham shall surely become a great and mighty nation, and all the nations of the earth shall be blessed in him? 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.