Whom God hath set forth to be a propitiation through faith in his blood, to declare his righteousness for the remission of sins that are past, through the forbearance of God;
God presented Christ as a sacrifice of atonement, through the shedding of his blood — to be received by faith. He did this to demonstrate his righteousness, because in his forbearance he had left the sins committed beforehand unpunished —
ὃν προέθετο ὁ Θεὸς ἱλαστήριον, διὰ τῆς πίστεως, ἐν τῷ αὐτοῦ αἵματι, εἰς ἔνδειξιν τῆς δικαιοσύνης αὐτοῦ, διὰ τὴν πάρεσιν τῶν προγεγονότων ἁμαρτημάτων,
on proetheto o Theos ilastērion, dia tēs pisteōs, en tō aytoy aimati, eis endeixin tēs dikaiosynēs aytoy, dia tēn paresin tōn progegonotōn amartēmatōn,