All our righteous acts are like filthy rags (Isaiah 64:6)
Isaiah 64:6 is, perhaps, one of the most cited verses to show that we should not (and could not) rely on our own righteousness for our salvation. Other favourite verse is Romans 3:10 that say no one is righteous. This leads to the concept of imputed righteousness of Christ to cover our unrighteousness. It is the concept adopted by Protestants and “Bible only” Christians in their justification. The suitable model for this justification is courtroom analogy where God is the judge and we are criminals, guilty of committed sins and are about to be thrown to jail (i.e. hell). God then offers the only solution – He sent His Son, Christ, a free gift from Him, and if we believe in Him, Christ will pay the penalty of our sins. This courtroom style or forensic justification fits well with Protestant’s belief that we are declared righteous through Justification. We take Christ righteousness while He takes our sins and bore them on the cross. This forensic Justification makes no room for purgatory and indulgences in Catholicism – Christ already paid the penalty of our sins, why are we still punished?
Catholics believe that our righteousness does come from God. By ourselves, because of original sin, we cannot produce any righteous acts. God, through Christ, helps us to become righteous but it needs our active cooperation. His help comes in the form of His Grace and this Grace will first move us to do righteous acts. Using our freedom we decide whether to cooperate with this given Grace or not. Scripture says: He who does right is righteous (1 John 3:7), indicating our active participation. Certainly we do need the righteousness that comes through faith (Romans 4:3, 13, Philippians 3:9). To do what is right includes believing in Christ, but it is not the only one we need. In Timothy 6:11 and 2 Timothy 2:22 Paul would not bother to ask Timothy to aim for righteousness – if the righteousness that comes through faith in Christ, which Timothy already had as Christian, was the only one he need. Is being righteous necessary? Scripture says whoever does not do right is not of God but the children of devil (1 John 3:10) and the unrighteous will not inherit the kingdom of God (1 Corinthians 6:9) while the righteous will go to eternal life (Matthew 25:46). The Psalmist cried: O LORD, who shall sojourn in thy tent? Who shall dwell on thy holy hill? (Psalms 15:1). The next verse gives the answer: He who walks blamelessly, and does what is right, and speaks truth from his heart. Christ said: “Blessed are those who hunger and thirst for righteousness, for they shall be satisfied” (Matthew 5:6) and “For I tell you, unless your righteousness exceeds that of the scribes and Pharisees, you will never enter the kingdom of heaven” (Matthew 5:20). Blessed are those who do righteousness at all times (Psalms 106:3). Keep in mind that being righteous is not the same as being sinless. “To do what is right” in 1 John 3:7 certainly includes “to repent” but nobody needs to repent unless he/she sins in the first place. Scripture says (Proverbs 24:16): “for a righteous man falls seven times, and rises again.”
Coming back to Isaiah 64:6 one should read not only that verse but the entire Isaiah 64 to see the context, as well as other part of the Bible. In fact Isaiah 64:5 says: Thou [God] meetest him that joyfully works righteousness, those that remember thee in thy ways. God blesses the righteous (Psalms 5:12), He loves righteous deeds (Psalms 11:7) and does reward us for being righteous (Psalms 18:20, Proverbs 11:18). Romans 3:10 say no one is righteous but at the same time Scripture mentions the existence of righteous men and women (Matthew 13:17, 23:29, Luke 1:6, Hebrews 11:4, 1 Peter 3:12). In Old Testament Noah, Daniel and Job were righteous (Ezekiel 14:14). No one can become righteous by their own will and power. We do need God’s grace that first moves us and enable us to do so. No one can be righteous continually either; we do fail from time to time. But God helps us with His Grace (and with our cooperation using our freedom) to stand up again and that’s what we call as perseverance. Thus Catholics believe that our righteousness does come from God through Christ – it includes not only faith in Christ but also other deeds that require our cooperation.
work out your own salvation with fear and trembling; for God is at work in you, both to will and to work for his good pleasure
But by the grace of God I am what I am. and his grace toward me was not in vain. On the contrary, I worked harder than any of them, though it was not I, but the grace of God which is with me
1 Corinthians 15:10
Catholics do not use courtroom analogy to model Justification. The most suitable analogy to describe Catholic’s understanding of Justification is Family analogy. God is our Father and we are His (adopted) children. Adoption as sons of God is something biblical that Protestants also believe (cf. Romans 8:15, 23, Galatians 4:5, Ephesians 1:5). However their forensic Justification model cannot fit in the Family analogy. We are not only declared sons but also made and become sons (John 1:12, 1 John 3:1 & 5:1), become heir with Christ (Romans 8:17) and partake His divinity (2 Peter 1:4). In Family analogy we receive our adoption through our faith in Christ (Galatians 3:26), not because of any righteous (or unrighteous) things we did – faith in Christ is a free gift from God. Once belong to the family of God, we have our duties and must obey household rules. No good human father will tell his children that because they are his, they can do whatever they like and there are no rule to obey and no duty in the house. At the same time a father won’t tell his friends that his children must work in his house in order not to be thrown out of the house. Any human father wants his children to grow up and to become good persons, not to become criminals, drug addicts, prostitutes etc. and he is more than willing to help his children to achieve that goal. For example he is willing to spend money for their education (free gift from him, not student loan). He spent time with his children to teach them not to associate with wrong companies; he makes sure they are in good health etc. Obviously his children must cooperate with him and do their part. Just because the father pays the tuition fee they will not get the degree or skills unless they study. If they do not listen to their father’s advice they may end up becoming member of gangs or drug addicts. Any human father will discipline his children for their own good when they do something wrong and reward them for being good (be it ice cream treat, a new bike etc.). The reward is obviously a gift from the father, not their wages for being good. Similarly our heavenly Father wants us, his children, to learn, to grow, to do our duty and to become mature, that is, to become like Him (Philippians 2:14). In the process He will also sometime discipline us for our own good (Hebrews 12:6) and will reward us, a gift from Him, when we well behave. This family analogy fits well with Catholic understanding of Justification – it is a process through which we are made righteous.