A commonly held belief of Protestants, speaking in general terms, is that via grace we’re offered forgiveness and we don’t need to become righteous; Christs’ righteousness is imputed to us instead, so long as we believe in Him and what He did for us. Catholics OTOH, believe that via grace we’re not only forgiven, but also empowered to ‘go, and sin no more’, to truly become righteous, as Christ is, with our cooperation being a necessary part in this process of justification.
From
this link:
[T]he doctrine of Sola Fide is patently absurd on the face of it since the act of believing is, in and of itself, a work. Simple logic says so, but Scripture itself also says so. John 6:27-29, “‘Do not labor for the food which perishes, but for the food which endures to eternal life, which the Son of Man will give to you’…Then they said to Him, ‘What must we do, to be doing the works of God?’ Jesus answered them, ‘This is the work of God, that you believe in Him Whom He has sent.’”
Jesus tells His listeners that they should “labor” for the food which endures to eternal life. If Sola Fide is true, why is He telling them to labor for anything in regard to eternal life? Then, when they ask what they must “do” to be doing the works of God, what does Jesus say? He says that believing in Him is the work of God that they must do. Believing is a work, according to Jesus Christ.
Some will say, “Wait a minute, John, Jesus says that believing is a work of God, not a work of man.” Leaving aside for a moment the question of whose work it is, it needs to be pointed out that the Word of God very clearly states that the act of believing is a work. Which is the point I’ve been making. Now, once we’ve made the point, using the Bible, that believing is indeed a work, then the question becomes, whose work is it? Is it a work of God, a work of man, or a work of God and man?
It is indeed a work of God, but, as the context of John 6:27-29 clearly shows, it is a work that God does through man and with man’s cooperation. Jesus tells the people to labor for the food that endures to eternal life. The people obviously want to follow Jesus’ instructions, so they ask him what it is they have to do. Did Jesus say, “Why do you ask what work you can do? Do you not know that you can do no work to receive the food which endures to eternal life?” No! That would be a pretty ridiculous thing for Him to say right after He told them they needed to “labor” for that very food.
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Scripture tells us that faith is completed by works. Or, again, as the KJV states it, faith is “made perfect” by works. If faith alone is necessary, then how can faith be completed, or perfected, by works? Wouldn’t we need a complete faith, a perfect faith, rather than an incomplete or imperfect faith to be saved? And do you see how verse 21 says Abraham was justified by works and verse 23 says “Abraham believed God, and it was reckoned to him as righteousness?” He believed and he did. Verse 21 is not in opposition to verse 23, it complements it. Faith and works.
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I absolutely love James 2:26. This is a verse that every Catholic ought to have memorized: “For as the body apart from the spirit is dead, so faith apart from works is dead.” This is a nifty little analogy that I love pointing out to anyone who says that faith without works really isn’t faith.
The analogy is that works are to faith, as the spirit is to the body. Just as a body without a spirit is a dead body, so faith without works is a dead faith. I always ask the question, “Are the bodies down at the morgue real bodies or not?” Yes, they are real bodies, but they are real dead bodies. Just so faith without works is indeed real faith, but it is real dead faith. This verse makes abundantly clear, as both body and spirit are necessary for physical life, then, for the analogy to hold, both faith and works are necessary for spiritual life. Just as the body alone does not give physical life, so faith alone does not give spiritual life.