1:2foreknowledge. Includes God’s sovereign, loving, effective choice and purpose (Rom. 8:29 note). The corresponding verb (“foreknown”) is used of Christ in v. 20.
in the sanctification of the Spirit. Note the close connection of the Father’s electing love with the Spirit’s work of applying redemption to the elect (2 Thess. 2:13). This “sanctification” includes all the Spirit’s operations in setting sinners apart from sin (including regeneration and faith) and purifying them for God’s service (sanctification in the progressive sense).
obedience. The initial act of obedience is faith in Christ (John 6:28, 29) and the fundamental element of all obedience is continued faith. To suggest that election is on the basis of God’s foreknowledge (that is, mere foresight) of faith would introduce a contradiction into this verse, since election is “for” or with the goal of faith (obedience), and not because of it (Eph. 1:3, 4; 2 Tim. 1:9).
his blood. Sprinkling of blood was part of the Old Testament ritual service. In general, the appearance of blood advertises the death of a victim. Abel’s blood cried for vengeance (Gen. 4:10), and Jesus’ blood cries for forgiveness (Luke 23:34; Heb. 12:24). In the worship of the Old Testament, the death of the victim establishes a covenant, and the sprinkling incorporates the worshipers as participants, making them publicly liable for the covenant’s benefits and responsibilities (Ex. 24:8).
grace and peace. This greeting is also a blessing, and would have special relevance for suffering Christians. Grace is God’s loving favor to sinners in Christ, while peace is the objective condition of being right with God through Christ (Rom. 5:1, 2), together with all that flows from that relationship. This verse proclaims all three persons of the one God who blesses. See “One and Three: The Trinity” at Is. 44:6.