What saith the Scripture

 Galatians 2:11–13 (NRSVue) 11 But when Cephas came to Antioch, I opposed him to his face because he stood self-condemned, 12 for until certain people came from James, he used to eat with the gentiles. But after they came, he drew back and kept himself separate for fear of the circumcision faction. 13 And the other Jews joined him in this hypocrisy, so that even Barnabas was led astray by their hypocrisy. Galatians 2:18 (NRSVue) 18 But if I build up again the very things that I once tore down, then I demonstrate that I am a transgressor. What Peter has first pulled down is the wall of partition between Jews and Gentiles. With his yielding to the party of James he is now building this up again and characterising his previous attitude as παράβασις transgression, and himself as παραβάτης transgressor, violator.  The contrast between “destroy” (καταλύω, katalyō) and “rebuild” (πάλιν οἰκοδομέω, palin oikodomeō) refers most naturally to the law: if Peter, as a Jewish Christian, should try to

  Justification by Faith Alone (The Relation of Faith to Justification ) Dr. Joel R. Beeke Justification by faith alone was Martin Luther's great spiritual and theological breakthrough. It did not come easily. He had tried everything from sleeping on hard floors and fasting to climbing a staircase in Rome while kneeling in prayer. Monasteries, disciplines, confessions, masses, absolutions, good works-all proved fruitless. Peace with God eluded him. The thought of the righteousness of God pursued him. He hated the very word "righteousness," which he believed provided a divine mandate to condemn him. Light finally dawned for Luther as he mediated on Romans 1:17, " For therein is the righteousness of God revealed from faith to faith: as it is written, The just shall live by faith ." Justification by Faith Alone (The Relation of Faith to Justification) by Joel Beeke