One response to a Catholic view of the necessity of good works for our salvation we may hear is that all of our works are like “filthy rags” to God.
This is a reference to Isaiah 64:6 where the prophet rails at Israel “We have all become like one who is unclean, and all our righteous deeds are like a polluted garment.” Other translations like the KJV translate “polluted garment” as “filthy rags.”
From the Catholic perspective it is most problematic when this verse is removed from its immediate context and then used to apply to every good work a person may do in every situation. Does God really consider every good work by any person in all eternity as a “filthy rag”? Such an idea is not supported by Sacred Scripture at all.
Context is everything. Although Israel at that time may have been performing the required works of the Mosaic law, by their actions they revealed they did not truly desire God or His ways. It was a case of “going through the motions” to keep the letter of the law but the Spirit of the law had faded from their lives. And Isaiah is trying to jolt them into that awareness and bring them back to the heart of truly serving God, not themselves.
Even in the previous verse, the prophet says “Thou meetest him that joyfully works righteousness, those that remember thee in thy ways” (Isaiah 64:5). This acknowledges that God indeed does recognize some works as being righteous. He then goes on so speak of Israel’s sin and how they have fallen away from any true works of righteousness in the eyes of God. And at that moment in time, their works were indeed “filthy rags” because of their unrepentant sin and a belief that God would overlook that if they just did the right “things” as well. But earlier in the text Isaiah notes that there were those who kept God’s sabbath and chose things that pleased Him (Isaiah 56:4-5). His admonition didn’t even apply to all of Israel at that moment in time, much less all believers of all time.
When we leave the immediate context of that verse and move into the whole of Scripture, it is quite clear that God does not view all works as “filthy rags.” We see an early example in the offering of Abel (Genesis 4:4) which God finds acceptable because he offered the first of his flock to God, as compared to his brother Cain who brought “some” of his crop. Hebrews 11:4 tells us that “By faith Abel offered to God a more acceptable sacrifice than Cain, through which he received approval as righteous.” We see that God viewed Noah as a righteous man who walked with Him (Genesis 6:9). Solomon pleased God when he asked for the gift of understanding (1 Kings 3:9-10). Psalm 51:17 tells us that “The sacrifice acceptable to God is a broken spirit; a broken and contrite heart, O God, thou wilt not despise” and Proverbs 21:3 that “To do righteousness and justice is more acceptable to the Lord than sacrifice.”
The New Testament has multiple passages that indicate many things we do are pleasing and acceptable to God. We are to “lead a life worthy of the Lord, fully pleasing to him, bearing fruit in every good work and increasing in the knowledge of God” (Colossians 1:10), to “present your bodies as a living sacrifice, holy and acceptable to God” (Romans 12:1), God finds it acceptable that we intercede for those in authority (1 Timothy 2:1-3), and that “he who thus serves Christ is acceptable to God and approved by men” (Romans 14:18). Sacred Scripture says of Zechariah and Elizabeth “they were both righteous before God, walking in all the commandments and ordinances of the Lord blameless” (Luke 1:6), St. Joseph was a “just” man (Matthew 1:19), and Mary had found favor with God (Luke 1:30).
And in the book of Acts we find Cornelius, a Gentile man who has not yet heard the Gospel. Yet he is told by the angel sent by God that “your prayers and your alms have ascended as a memorial before God” (Acts 10:4). This is quite a contrast to Christ’s words to the Pharisees that “Woe to you, scribes and Pharisees, hypocrites! for you are like whitewashed tombs, which outwardly appear beautiful, but within they are full of dead men’s bones and all uncleanness. So you also outwardly appear righteous to men, but within you are full of hypocrisy and iniquity” (Matthew 23:27-28).
The lesson to be learned from Isaiah’s message to the Israelites that their works are seen by God as “filthy rags” is the same message Christ has for the scribes and Pharisees. All of the works done for “show” but without an inward disposition of true charity are indeed not pleasing to God. But Sacred Scripture attests over and over that those works that truly come forth from love are most pleasing and acceptable to God. We are to strive for such works, and our efforts will indeed be rewarded (2 Corinthians 5:10).