Gospel is spelled “d-o-n-e,” not “d-o”. The word “Gospel” implies an event that has already been done, not something we must go and do. The Gospel is not, then, primarily about what we are to go and do for God, but about what God has done for us. The Gospel is good news, not good advice.
The core message of that good news is that God saves sinners. From start to finish, it is all God’s work, not ours.
Christ saved us by substituting for us. He lived the life we were supposed to have lived, and died the death we were condemned to die. Whatever “metaphor” you choose for salvation–justification, redemption, cleansing, defeat of the evil powers–substitution is the core of it. For example, Christ’s blood cleanses us… but how? Because He substituted for us and absorbed the curse, corruption and condemnation for sin.
The Gospel is only good news if it gets there in time.
Read more from J.D. Greer on his blog