Some sins seem bigger then others because of their obvious consequences are much more serious. Murder, for example, seems to us to be worse then hatred, and adultery seems worse then lust. But this does not mean that because we do lesser sins we deserve eternal life. All sin makes us sinners, and all sin cuts us off from our holy God. All sin, therefore, leads to death (because it disqualifies us from living with God), regardless of how great or small it seems. Don’t minimize “little” sins or overrate “big” sin. They all separate us from God, but all can be forgiven.
King David was guilty of terrible sins- adultery, murder, and lying- and yet he experienced the joy of forgiveness. We too can have this joy when we (1) quit denying our guilt and recognize that we have sinned, (2) admit our guilt to God and ask for His forgiveness, and (3) let go of our guilt and believe that God has forgiven us.