(By Faith and through Faith..)
More...”Consequently, just as the result of one trespass was condemnation for all men, (through Adam), so also the result of one act of righteousness (through Christ) was ‘Justification’ that brings life for all men. For just as through disobedience of the one man (Adam) many were made sinners, so also through the obedience of the one man (Christ) many will be made righteous. Romans 5:18,19
The Just shall live by faith seems to be very much supported by the scripture.
Additionally....”the word of FAITH we are proclaiming: That if you confess with your mouth, Jesus is Lord, and believe in your heart that God raised him from the dead,...you shall be saved....For it is with your heart that you believe and are JUSTIFIED and it is with your mouth that you confess and are SAVED. Romans10:9,10
Some Christians are admonished for having what is called a "presumption" of eternal life - like it is a BAD thing????!!! We say we know we have eternal life because it is a hope and assurance given to us by God himself through his own words. We are saved not because we presume we are worthy, but because we KNOW we are unworthy and it is only through the grace of God by faith alone that we have this blessed hope.
On the other hand, those who rely on their own merits and deeds can never know that blessed assurance because they know their own sinful leanings. They need to constantly be reassured through works and deeds and penances and external signs of grace and, even then, not really having it for sure. The motivation for good works is based on fear and not to the glory of God out of a grateful heart. How much that must grieve our Savior!