What happens if you add works to faith to complete your salvation?
Adding works to faith to complete salvation cancels the work of the cross. Scripture says Christ profits you nothing in that case, and such a person is lost. Salvation rests entirely on what Christ accomplished on the cross, not on circumcision, baptism, church membership, or any fleshly deed.
Les teaches that if a person is doing something to fulfill salvation—trying to put the frosting on the cake—they are lost as lost can be, because the Book says so. In that situation Christ can profit them nothing. The only way anyone enters God's heaven is by what Christ profits on their behalf. Les warns people not to depend on something they can do. In this case it was circumcision, but it can be anything: church membership, baptism, or any fleshly act. When such works are made part of salvation, they cancel the work of the cross. Christ's words “It's finished” mean everything needed was accomplished on that cross.