What does God's dealing with us in grace require us to believe?
Grace requires believing that God has done everything that needs to be done, and that Christ finished the work of the cross. Salvation is all of grace by faith plus nothing else; adding anything denies that finished transaction. It requires trusting His finished work rather than legalistic demands.
Les teaches that this is the whole concept of God's dealing with us in grace: we must believe that He did everything that needs to be done. As soon as we try to add to it, we are actually saying Christ did not really finish it, but He did. God has revealed in His Word, especially through the Apostle Paul, that it was finished, and we stand justified, forgiven, sanctified, and glorified simply because we believe it is a finished transaction. This is what Galatians shows: we are not under law or legalistic demands for salvation; salvation is all of grace by faith plus nothing else. The Galatians were tempted to return to legalism, at that time prompted by the Jews and circumcision. For us today circumcision is not the criterion, but other things people say we must do besides believing the Gospel.