James 2:23 And the scripture was fulfilled which saith, Abraham believed God, and it was imputed unto him for righteousness: and he was called the Friend of God.
Abraham was "the Friend of God". We are Abraham's children through faith in Christ.
Galatians 3:6-14 Even as Abraham believed God, and it was accounted to him for righteousness. Know ye therefore that they which are of faith, the same are the children of Abraham. And the scripture, foreseeing that God would justify the heathen through faith, preached before the gospel unto Abraham, saying, In thee shall all nations be blessed. So then they which be of faith are blessed with faithful Abraham. For as many as are of the works of the law are under the curse: for it is written, Cursed is every one that continueth not in all things which are written in the book of the law to do them. But that no man is justified by the law in the sight of God, it is evident: for, The just shall live by faith. And the law is not of faith: but, The man that doeth them shall live in them. Christ hath redeemed us from the curse of the law, being made a curse for us: for it is written, Cursed is every one that hangeth on a tree: That the blessing of Abraham might come on the Gentiles through Jesus Christ; that we might receive the promise of the Spirit through faith.
Abraham lived by faith, not the Law (Rom. 4:12). He didn't even have the Law in his day, though he did know right from wrong since the law is written in every heart (Rom. 2:14-15). But, a friend likes to please his friend. Abraham obviously desired to please God, and he believed God. God knew that Abraham desired to please Him and He honored that.