Hi Robby, thank you for your comment! If you owe someone $20, and your buddy pays it without you knowing, you are forgiven that debt by the person holding the debt. You may not know it's paid, but it's paid, and it can never be brought up in court against you as having not been paid. You ARE FORGIVEN that debt!
When you understand the debt has been paid, you can either try to pay it anyway (which is kind of foolish isn't it?), or you can accept that it has been paid by someone else and reap the benefit of it for as long as the person who paid the debt lives! He is the only witness that can testify it was paid.
Forgiveness has taken place through the person of Jesus Christ. There is nothing left to do after receiving that truth. Receiving the gospel and accepting the payment Christ has already made is receiving His already made provision of forgiveness! In Gods book your account is clean and have been forgiven the only thing left between you and Him which was unbelief. He will never hold our sins against us because they were already removed 2,000 years ago by His Son before we were even born. Once we have trusted in His Sons sacrifice for sin and resurrection from the dead, we are "in Christ", and there is NOTHING that can ever come between us and God again!