Romans 3:25-26

God presented him as a sacrifice of atonement through faith in his blood. He did this to demonstrate his justice, because in his forbearance he had left the sins committed beforehand unpunished--he did it to demonstrate his justice at the present time, so as to be just and the one who justifies those who have faith in Jesus.

God presented him as a sacrifice of atonement
Hebrews 2:17 For this reason he had to be made like his brothers in every way, in order that he might become a merciful and faithful high priest in service to God, and that he might make atonement for the sins of the people.
Hebrews 9:28 ... so Christ was sacrificed once to take away the sins of many people; and he will appear a second time, not to bear sin, but to bring salvation to those who are waiting for him.
1 John 4:10 This is love: not that we loved God, but that he loved us and sent his Son as an atoning sacrifice for our sins.

through his blood
Romans 5:9 Since we have now been justified by his blood, how much more shall we be saved from God's wrath through him!
Ephesians 1:7-8 In him we have redemption through his blood, the forgiveness of sins, in accordance with the riches of God's grace that he lavished on us with all wisdom and understanding.
Hebrews 9:12 He did not enter by means of the blood of goats and calves; but he entered the Most Holy Place once for all by his own blood, having obtained eternal redemption.
Hebrews 9:14 How much more, then, will the blood of Christ, who through the eternal Spirit offered himself unblemished to God, cleanse our consciences from acts that lead to death, so that we may serve the living God!
Hebrews 13:12 Ad so Jesus also suffered outside the city gate to make the people holy through his own blood.
1 Peter 1:18-19 For you know that it was not with perishable things such as silver or gold that you were redeemed from the empty way of life handed down to you from your forefathers, but with the precious blood of Christ, a lamb without blemish or defect.

because in his forbearance he had left the sins committed beforehand unpunished
Acts 14:16 In the past, he let all nations go their own way.
Acts 17:30 In the past God overlooked such ignorance, but now he commands all people everywhere to repent.

NOTES:
Read Romans 8

Scriptures taken from the Holy Bible, New International Version® NIV®, Copyright© 1973, 1978, 1984 by International Bible Society. Used by permission. All rights reserved worldwide.