John Calvin Commentary Romans 9:33

"even as it is written, Behold, I lay in Zion a stone of stumbling and a rock of offence: And he that believeth on him shall not be put to shame." — Romans 9:33 (ASV)

And every one who believes in him shall not be ashamed. He adds this testimony from another passage for the comfort of the godly; as if he had said, “Because Christ is called the stone of stumbling, there is no reason that we should fear him, or be fearful instead of confident; for he is appointed for destruction to the unbelieving, but for life and resurrection to the godly.”

Just as the former prophecy concerning the stumbling and offense is fulfilled in the rebellious and unbelieving, so there is another prophecy intended for the godly: that he is a firm stone, precious, a cornerstone, most firmly fixed, and whoever builds on it shall never fall.

By using shall not be ashamed instead of shall not hasten or fall, he has followed the Greek Translator. It is indeed certain that the Lord in that passage intended to strengthen the hope of his people.

And when the Lord instructs us to have good hope, it follows from this that we cannot be ashamed. See a similar passage in 1 Peter 2:10.