The joy of the gospel does not come from feeling guilty of our sins. Guilt brings death. Guilt brings the will to stop living.
The joy of the gospel comes from knowing that because Jesus died we now have a father-child relationship with God.
“It was the last and most important day of the Feast. Jesus stood up and spoke in a loud voice. He said, "Let anyone who is thirsty come to me and drink. Does anyone believe in me? Then, just as Scripture says, streams of living water will flow from inside him." When he said this, he meant the Holy Spirit. Those who believed in Jesus would receive the Spirit later. Up to that time, the Spirit had not been given. This was because Jesus had not yet received glory.” (John 7:37-39)