Adam Clarke on Psalms 85:2

Thou hast forgiven the iniquity - נשאת עון nasatha avon, Thou hast borne, or carried away, the iniquity. An allusion to the ceremony of the scapegoat.

Thou hast covered all their sin - As thou hast freely forgiven it, its offensiveness and abominable nature no longer appear. The whole is put out of sight; and, as we are restored from our captivity, the consequences no longer appear.

Selah - This is true. Our return to our own land is the full proof.