Says this: the whole time of your faith will not profit you, if you are not made perfect in the last time.
Is Catholic: Section 8: He sought to form a mind conscious of righteousness, so that being convinced in that time of our unworthiness of attaining life through our own works, it should now, through the kindness of Gob, be vouchsafed to us; and having made it manifest that in ourselves we were unable to enter into the kingdom of God, we might through the power of God BE MADE ABLE.
And then: He who takes upon himself the burden of his neighbour; he who, in whatsoever respect he may be superior, is ready to benefit another who is deficient; he who whatsoever thing he has received from God, by distributing these to the needy, becomes a god to those who receive his benefits: he is an imitator of God. Then thou shalt see, while still on earth that God in the heavens rules over the universe; then thou shalt see, while still on earth that God in the heavens rules over the universe; then thou shalt begin to speak the mysteries of God; then shalt thou both love and admire those that suffer punishment because they will not deny God
Also Catholic:
CHAP. XXX.–LET US DO THOSE THINGS THAT PLEASE GOD, AND FLEE FROM THOSE HE HATES, THAT WE MAY BE BLESSED.
Seeing, therefore, that we are the portion of the Holy One, let us do all those things which pertain to holiness, avoiding all evil-speaking, all abominable and impure embraces, together with all drunkenness, seeking after change,(3) all abominable lusts, detestable adultery, and execrable pride. "For God," saith [the Scripture], "resisteth the proud, but giveth grace to the humble."(4) Let us cleave, then, to those to whom grace has been given by God. LET US CLOTHE OURSELVES WITH CONCORD AND HUMILITY, EVER EXERCISING SELF-CONTROL, STANDING FAR OFF FROM ALL WHISPERING AND EVIL-SPEAKING, BEING JUSTIFIED BY OUR WORKS, AND NOT OUR WORDS. For [the Scripture] saith, "He that speaketh much, shall also hear much in answer. And does he that is ready in speech deem himself righteous? Blessed is he that is born of woman, who liveth but a short time: be not given to much speaking."(5) Let our praise be in God, and not of ourselves; for God hateth those that commend themselves. Let testimony to our good deeds be borne by others, as it was in the case of our righteous forefathers. Boldness, and arrogance, and audacity belong to those that are accursed of God; but moderation, humility, and meekness to such as are blessed by Him.
When he made the quote that you noted, we see that surrounding it before and after was the necessity of works done in God's grace for salvation. He was in the quote contrasting a self-righteous holiness to the holiness that must be done in God's grace. The one that did not justify, is when one tries to justify himself, relies on his own wisdom, holiness, etc. One indeed who works on one's own power is condemned by Trent, canon 1, justification. That is what Clement was condemning, and saying that does not avail before God. He specifically speaks of justification by works in Chapter 30. Notice though that those works are done in grace, as he specifically says in that same chapter. In Chapter 31 he says Abraham was blessed (and the context is speaking of justification), because of the act of offering Isaac on the altar. In chapter 34, Clement says that in justification it is requisite to our actions to be well-doing. He gives us two choices. To be a faithful servant, we labor (in grace of course) and we get the reward of heaven. However, if we are a slothful servant, and don't labor for God, we are sent to hell. Clement is obviously referring to Mt. 24:45-51. The slothful servant gets what? weeping and gnashing of teeth. That is hell. Why, because he didn't work. Then Clement says, he forewarns us he renders accoring to our works (Rom. 2:6, Mt. 16:27). If faith alone, he wouldn't forewarn us (because our justification would be absolutely assured), and we would not fear damnation. In Chapter 48 he speaks of those can attain salvation only those who direct their ways in holiness. Thus, that direction in holiness is a cause of justification. In Chapter 50 he notes that we must keep the commandments and that love (not faith alone) forgives sins. Clement notes that works are what must be judged before God to achieve salvation, and not even a hint of forensic justification, or Sola Fide.
As for use of elect, it's not what you think: jimmyakin.com/2017/11/gods-elect-in-1-clement.html