Sin

Psalm 85:2 You forgave the iniquity of your people; you covered all their sin. Selah. . . . #Bible
The Lord forgave their iniquity, He lifted up and took away the punishment for their perversity, depravity, iniquity, and guilt. The idea is that of the ceremony of the scapegoat.
Covered all their sin, which were counted and hidden. I feel like this is what God did in the Garden of Eden with Adam and Eve. After they sinned eating the forbidden fruit, God covered them.
Gen 3:21 KJV Unto Adam also and to his wife did the LORD God make coats of skins, and clothed them.
The difference between Israel and Christians is, Israel sins were either placed on the head of a scapegoat and sent into the wilderness to be forgotten, or they were covered, out of sight.
All sin was forgiven completely when Jesus the Christ, the Messiah satisfied God's requirement for sin, "the soul that sins will surely die".
Jesus laid His Life down on the cross so we could pick our lives up from death caused by our sin.
 “For God loved the world in this way: He gave His One and Only Son, so that everyone who believes in Him will not perish but have eternal life.  For God did not send His Son into the world that He might condemn the world, but that the world might be saved through Him.  Anyone who believes in Him is not condemned, but anyone who does not believe is already condemned, because he has not believed in the name of the One and Only Son of God. - John 3:16-18