Romans 4:3  For what saith the scripture? Abraham believed God, and it was counted unto him for righteousness. 

Paul appeals to Scripture as the final authority, not church history or church tradition. When was Abraham declared righteous? Was it when he was circumcised in Genesis 17? Was it when he offered up Isaac on Mount Moriah in Genesis 22? No, it was in Genesis 15:6 when he believed God after He told him that he and Sarah would have a child.  God promised an heir to Abraham, and, although it seemed contrary to nature in light of his and Sarah’s ages, he believed the promise. 

There is no honor, merit or boasting when a person believes the promise of God Almighty Who cannot lie! Believing is not a work on our part; it’s a response to the promise of God. “And this is the record, that God hath given to us eternal life, and this life is in his Son.” (1 John 5:11) Now, the public testimony of Abraham’s faith was when he was circumcised in Genesis 17, and the evidence of the genuineness of his faith was when he offered up Isaac in obedience to God’s command in Genesis 22, but he was saved, using New Testament terminology, in Genesis 15, the very moment that he believed God, long before either of those outward actions. 

Water baptism and good works are the fruit of saving faith, never the cause or root of it. Thanks be unto God for His unspeakable gift!