The covenant of redemption (pactum salutis) is the eternal, inter-Trinitarian agreement made before creation: the Father appoints the Son as Redeemer, the Son willingly agrees to fulfill that role, and the Spirit sanctifies those the Son redeems – all part of God’s plan declared ‘from the beginning’ (Isaiah 46:9-10).
From this covenant flow the blessings of Ephesians 1: election before the foundation of the world, adoption as sons, redemption through Christ’s blood, the revealed mystery of His will, and the sealing of the Spirit as a pledge of our inheritance – every one of them, Paul says, ‘to the praise of His glory.’