Blessed [makarios] are they whose [hos]
iniquities [anomia] are forgiven [aphiemi], and [kai] whose [hos] sins [hamartia] are covered
are those whose lawless deeds are forgiven, and whose sins are covered; ESV
The word for forgiven, ‘aphiemi,’ means to be sent away, to be forgotten. The word for covered, ‘epikalupto,’ means to be covered so as to not be seem, or never seen again, covered, buried, gone permanently from sight, from consciousness, from memory.
True blessing is the removal of all sins and transgressions away from ones life, such that they will never be seen again, and will be permanently forgotten.
Only God is able to do this.
Most people spend a great deal of effort in remembering the sins or failures of others. They of course conveniently forget their own errors. But that is the human in us. Problems are much bigger and unforgettable, when they belong to someone else. And of course they make it easy to criticize others while promoting oneself or elevating oneself at least within ones own ego.
But God, forgets, in the true sense of forgetting, in that God never brings sins or transgressions or errors up again. Only people do that.
So, sins were paid for in full, when Jesus Christ went to the cross. That means the debt is paid in full and no further payment is due or even required, and never will be required. The debt is cancelled, paid in full, torn up, buried, discarded.
But more than that, the removal and covering is something that is not accomplished by us, but is done by God and God alone. This eliminates works as the mechanism for the removal of sins.
The blessing comes not from our own source, but from an external source, apart from us. The removal and covering likewise is not of our own doing but the doing of another, namely God.