Have you considered that perhaps the same faith of Abraham, was the same faith of our Lord and Savior Christ Jesus, as it is the same of those saved today?
Rom 3:22-26
But don't stop there! ;-) If we keep reading we see Romans chapter 4 tells how Abraham was justified by faith. In the middle of chapter 4 Paul tells us (verse 16) "therefore the promise comes by faith." As we keep reading we see chapter 5 starts with... another "therefore." Well, therefore what? "Therefore since we have been justified by faith"...
So as we continue reading past Romans 3:22-26, we see your statement is most definitely supported from Paul.