Audio commentary on this verse

Note 7 at Ro 10:6: Paul was saying that failure to understand justification by grace produces an attitude that, in effect, denies Christ's substitutionary work for us. Those who still believe that their performance is essential for salvation are denying that Christ is in heaven, making intercession for man (Ro 8:34). That dethrones Christ from His present position. It is like denying that Christ has ascended into heaven for us.

Likewise, a belief that we have to bear the punishment for our sins is like denying that Christ's death was sufficient by itself. If we are to be punished for our sins, then Christ might as well not have died for us.

All of this is continuing what Paul began in Ro 10:5, contrasting the doing of the Old Testament Law and the believing of the New Testament grace (see note 5 at Ro 10:5). The Law mentality puts us under an unbearable load of performance to obtain righteousness; faith just receives the righteousness that has already been provided through Christ.