Romans 10:6

But the righteousness which is of faith saith thus, Say not in thy heart, Who shall ascend into heaven? (that is, to bring Christ down:)

'But' -on the other hand.

'of faith' -a right standing with God that is the result of an obedient faith in God. (Romans 1:16) This infers that when. person is trying to 'merit or earn' God's favor (Romans 10:5), i.e. put God in debt, that there is no 'faith' involved in such. mind-set. Many of the Jew's didn't trust God for salvation, rather they thought that God owed them salvation. (Luke 18:9 ff)

'saith thus' -Note: The O.T. spoke of this 'righteousness of faith'. Paul now will quote from the Law, (Deuteronomy 30:12). Right standing with God based on 'obedient trust' had always been available to mankind. (Romans 1:17)

'Say not in thy heart, Who shall ascend into heaven?' -'Who will scale heaven for us' (Knox) To say in the heart is to think. 'To think secretly and is used especially regarding some unworthy thought which one fears to utter aloud' (Lenski p. 650)

'You don't have to do the impossible. You don't have to go up to heaven and persuade Christ to come down and die for you. That's already been done.' '