Since, therefore, Abraham was a prophet and saw in the Spirit the day of the Lord’s coming, and the dispensation of His suffering, through whom both he himself and all who, following the example of his faith, trust in God, should be saved, he rejoiced exceedingly. The Lord, therefore, was not unknown to Abraham, whose day he desired to see; nor, again, was the Lord’s Father, for he had learned from the Word of the Lord, and believed Him; wherefore it was accounted to him by the Lord for righteousness. For faith towards God justifies a man. (Irenaeus, Against Heresies, iv.v.5)
- It was the Triune God who revealed Himself in a Triune way to Abraham - Abraham saw in the Spirit the Lord's coming and suffering and through the Lord knew the Lord's Father. Jesus is the Revelation of God.
- Abraham was justified by faith - and so are we.
- Abraham wasn't justified by a vague belief in God, but by faith in Christ our God - Irenaeus tells us that the God in whom Abraham had faith was the Word of the Lord, the Lord who came and suffered for our salvation.