1 Peter 2:21-24 (KJV)
21 For even hereunto were ye called: because Christ also suffered for us, leaving us an example, that ye should follow his steps:
22 Who did no sin, neither was guile found in his mouth:
23 Who, when he was reviled, reviled not again; when he suffered, he threatened not; but committed himself to him that judgeth righteously:
24 Who his own self bare our sins in his own body on the tree, that we, being dead to sins, should live unto righteousness: by whose stripes ye were healed.
Jesus's death on the cross is what ushered in the forgiveness of sins to the world. Mercy is for anyone that receives Him as Lord.
On Good Friday we celebrate our Lord Jesus and His sacrifice for all mankind on the cross, in which there is payment for sins.