God said that those who live under the law must do it perfectly to be saved. He said no such thing about those who live by faith. The faith believers live by is what was given to them by God. God chooses to increase it through sanctification, but it is not due to the decision of the believer. I actually do not concern myself with trying to measure my faith as against anyone else's. I just try to follow God's leading. My faith will be what God wants it to be.
Obviously, it's the intent that counts and not perfection. The poor old woman who gives her last two copper coins to the synagogue is giving everything she has to God. A rich Pharisee who tithes 10% of his wealth is not, although his sum may be greater. Who is justified in the eyes of God? We all believe it's the woman for giving everything to God. I am sure both the woman and the Pharisee have faith, but that's not all that is required.
I don't think that God wants us to be in the mindset of trying to "one-up" each other by seeing who gives more. The old woman gave "more", but the Pharisee also did right by giving what God asked of him. Had God decided to move his heart, he would have given more. I do not look down at the Pharisee at all in this example. While I would not use the word "justified" in this example for either one, from the information we have I would not say that the woman deserves more personal credit. God decided to bless her with the higher faith of complete dependence.
This is the unbridgeable canyon between the Apostolic Church and Protestant mindset, the way Judaism is separate from Christianity in general. It involves a different interpretation of the Scripture.
The Jews read the same OT and don't see the foreshaddowing of Christ. God gives us faith. What we do with it is a different story. That is up to us. It's a credit. What you do with it, how you use it, spendt is, multiply it, with what intent reflects not what God gives us but what you do with His blessings.
Christ was very clear when He said that a wealthy man will not go to heaven, and when he said that unless your righteousness does not exceed the righteousness of the Pharisees you shall not enter the Kingdom.