A.T. Robertson Commentary Ephesians 1:7

"in whom we have our redemption through his blood, the forgiveness of our trespasses, according to the riches of his grace," — Ephesians 1:7 (ASV)

In whom (εν ω). Just like Col 1:14 with παραπτωματων (trespasses) in place of αμαρτιων (sins) and with the addition of δια του αιματος αυτου (through his blood) as in Col 1:20. Clearly Paul makes the blood of Christ the cost of redemption, the ransom money (λυτρον, Matthew 20:28; αντιλυτρον, 1 Timothy 2:6). See Col 1:9.