…first of all I commend you for seeking out Sacred Scriptures–the book of Wisdom has a wonderful take on what you are doing!
You are correct, non-Catholic Christians sometimes hold on to their respective group’s interpretation of what they believe (think) Scripture is stating… yet, as it has been noted on the previous posts: there is no assurance of Salvation (outside of Christ Jesus) nor is there Salvation by Faith alone.
Personally, I find that St. John 15:1-10 is the clearest deliberation, by Christ Himself, that Salvation is not dependent upon Faith alone nor is it received once and for all; specifically:
3 You are clean already, by means of the word that I have spoken to you.
4 Remain in me, as I in you. As a branch cannot bear fruit all by itself, unless it remains part of the vine, neither can you unless you remain in me. (John 15:3-4)
Jesus states that His Disciples (the Twelve) have been separated from the world (Saved) through His Word (Teachings); yet, He insists that they must remain in Fellowship (Faith and Works) with Him for outside of Him there is no Salvation!