25 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-
25 Whom God hath set forth set forth: or, foreordained 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;
English Standard Version
25 whom God put forward as a propitiation by his blood, to be received by faith. This was to show God's righteousness, because in his divine forbearance he had passed over former sins.
25 God sacrificed Jesus on the altar of the world to clear that world of sin. Having faith in him sets us in the clear. God decided on this course of action in full view of the public - to set the world in the clear with himself through the sacrifice of Jesus, finally taking care of the sins he had so patiently endured.
New King James Version
25 whom God set forth as a propitiation by His blood, through faith, to demonstrate His righteousness, because in His forbearance God had passed over the sins that were previously committed,
New Living Translation
25 For God presented Jesus as the sacrifice for sin. People are made right with God when they believe that Jesus sacrificed his life, shedding his blood. This sacrifice shows that God was being fair when he held back and did not punish those who sinned in times past,
Must guilty man remain under wrath? Is the wound for ever incurable? No; blessed be God, there is another way laid open for us. This is the righteousness of God; righteousness of his ordaining, and providing, and accepting. It is by that faith which has Jesus Christ for its object; an anointed Saviour, so Jesus Christ signifies. Justifying faith respects Christ as a Saviour, in all his three anointed offices, as Prophet, Priest, and King; trusting in him, accepting him, and cleaving to him: in all these, Jews and Gentiles are alike welcome to God through Christ. There is no difference, his righteousness is upon all that believe; not only offered to them, but put upon them as a crown, as a robe. It is free grace, mere mercy; there is nothing in us to deserve such favours. It comes freely unto us, but Christ bought it, and paid the price. And faith has special regard to the blood of Christ, as that which made the atonement. God, in all this, declares his righteousness. It is plain that he hates sin, when nothing less than the blood of Christ would satisfy for it. And it would not agree with his justice to demand the debt, when the Surety has paid it, and he has accepted that payment in full satisfaction.