It is an interesting exercise to read the letters to the seven churches in the book of Revelation. When I was a Protestant I just plain ignored the completely unambiguous language that the Lord Jesus Christ uses in speaking to and about them. Let’s take a look.
To the Church at Ephesus, He says (2:2,4-5):
I know your works, your toil and your patient endurance, and how you cannot bear evil men but have tested those who call themselves apostles but are not, and found them to be false…But I have this against you, that you have abandoned the love you had at first. Remember then from what you have fallen, repent and do the works you did at first. (Emphasis added)
To Thyatira He says (2:19):
I know your works, your love and faith and service and patient endurance, and that your latter works exceed the first. (Emphasis added)
To the Church at Sardis (3:1b-4):
I know your works; you have the name of being alive, and you are dead. Awake, and strengthen what remains and is on the point of death, for I have not found your works perfect in the sight of my God. Remember then what you received and heard; keep that, and repent. If you will not awake, I will come like a thief, and you will not know at what hour I will come upon you. Yet you have still a few names in Sardis, people who have not soiled their garments; and they shall walk with me in white, for they are worthy. (Emphasis added)
Short digression: note how God says that there are people in Sardis who have not soiled their garments (in other words, they are not living in unrepentant sin), and that these people are worthy. Worth bespeaks merit, does it not? But many Protestants deny that there is any sense in which we merit anything from God but judgment and death and hell. Let’s move on.
To Philadelphia He says (3:8a, 10):
I know your works. … Because you have kept my word of patient endurance, I will keep you from the hour of trial which is coming on the whole world, to try those who dwell upon the earth. (Emphasis added)
Lastly, to Laodicea, Christ says (3:15-16):
I know your works: you are neither cold nor hot. Would that you were cold or hot! So, because you are lukewarm, and neither cold nor hot, I will spew you out of my mouth. (Emphasis added)
In short: to five of the seven Churches Christ begins by saying “I know your works.” Now, if it were true (as Protestants claim) that we are saved by faith alone, then these words of Jesus make no sense whatsoever. Instead, we would expect Him to have said to them, “I know your faith.” But that is not what He says. Rather, he talks about their works: the things that they have done.
I am not intending to say here that we are saved by works. I do not believe that because the Catholic Church does not teach that. What I am saying is that these repeated appeals to Christians’ works make it flatly impossible that our deeds have nothing to do with whether we are saved or not. In short, Jesus’ words to the seven churches make the Protestant’s ideas about sola fide impossible.