While reading through 1 Clement, I found a nice example of justify (δικαιόω) being used in two different senses (in very close proximity), which nicely parallels its use in the New Testament.
Justified by Works
In this first example, Clement is calling his readers to personal holiness and speaks of their being justified by works (ἔργοις δικαιούμενοι). He seems to have in view a demonstration rather than imputation of righteousness.
30 Seeing then that we are the portion of the Holy One, let us do all the things that pertain to holiness, forsaking slander, disgusting and impure embraces, drunkenness and rioting and detestable lusts, abominable adultery, detestable pride. (2) “For God,” he says, “resists the proud, but gives grace to the humble.” (3) Let us therefore join with those to whom grace is given by God. Let us clothe ourselves in concord, being humble and self-controlled, keeping ourselves far from all backbiting and slander, being justified by works and not by words [ἔργοις δικαιούμενοι καὶ μὴ λόγοις]. (4) For he says: “He who speaks much shall hear much in reply. Or does the talkative person think that he is righteous? (5) Blessed is the one born of woman who has a short life. Do not be overly talkative.” (6) Let our praise be with God, and not from ourselves, for God hates those who praise themselves. (7) Let the testimony to our good deeds be given by others, as it was given to our fathers who were righteous. (8) Boldness and arrogance and audacity are for those who are cursed by God; but graciousness and humility and gentleness are with those who are blessed by God.
His use of justify is similar to Jesus’ use in Matthew 12:33–37:
“Either make the tree good and its fruit good, or make the tree bad and its fruit bad, for the tree is known by its fruit. You brood of vipers! How can you speak good, when you are evil? For out of the abundance of the heart the mouth speaks. The good person out of his good treasure brings forth good, and the evil person out of his evil treasure brings forth evil. I tell you, on the day of judgment people will give account for every careless word they speak, for by your words you will be justified [ἐκ γὰρ τῶν λόγων σου δικαιωθήσῃ], and by your words you will be condemned” (cf. Mt 11:19).
(This is tangential to the main point, but there is a notable difference between what Jesus says and what Clement says. Jesus says you will be justified by your words, and Clement says you aren’t justified by your words. But the difference is only apparent. Jesus is referring to words as fruit, the overflowing of the heart. In this sense, words are a form of works, not opposed to them. And words, like works, will demonstrate your righteousness or wickedness. Clement is trying to discourage boasting and encourage an active, humble faith. He’s arguing that shallow, prideful talking does not make or demonstrate one to be righteous, similar to what John argues in 1 John 3:16–18.)
James’s use of justify in James 2:21–24 seems to carry the same sense:
Was not Abraham our father justified by works [ἐξ ἔργων ἐδικαιώθη] when he offered up his son Isaac on the altar? You see that faith was active along with his works, and faith was completed by his works; and the Scripture was fulfilled that says, “Abraham believed God, and it was counted to him as righteousness”—and he was called a friend of God. You see that a person is justified by works [ἐξ ἔργων δικαιοῦται] and not by faith alone. And in the same way was not also Rahab the prostitute justified by works [ἐξ ἔργων ἐδικαιώθη] when she received the messengers and sent them out by another way?
As the Old Testament accounts bear out, what James is describing is the justification (sense 1) of the already justified (sense 2).
Justified by Faith
In the second example—just one paragraph later—Clement says that we are not justified through our works (οὐ διʼ ἑαυτῶν δικαιούμεθα οὐδὲ διὰ τῆς ἡμετέρας . . . ἔργων), but through faith (ἀλλὰ διὰ τῆς πίστεως).
32. If anyone will consider them sincerely one by one, he will understand the magnificence of the gifts that are given by him. (2) For from Jacob come all the priests and Levites who minister at the altar of God; from him comes the Lord Jesus according to the flesh; from him come the kings and rulers and governors in the line of Judah; and his other tribes are held in no small honor, seeing that God promised that “your seed shall be as the stars of heaven.” (3) All, therefore, were glorified and magnified, not through themselves or their own works or the righteous actions which they did, but through his will. (4) And so we, having been called through his will in Christ Jesus, are not justified through ourselves or through our own wisdom or understanding or piety or works which we have done in holiness of heart, but through faith, by which the almighty God has justified all who have existed from the beginning [οὐ διʼ ἑαυτῶν δικαιούμεθα οὐδὲ διὰ τῆς ἡμετέρας σοφίας ἢ συνέσεως ἢ εὐσεβείας ἢ ἔργων ὧν κατειργασάμεθα ἐν ὁσιότητι καρδίας, ἀλλὰ διὰ τῆς πίστεως, διʼ ἧς πάντας τοὺς ἀπʼ αἰῶνος ὁ παντοκράτωρ θεὸς ἐδικαίωσεν]; to whom be the glory for ever and ever. Amen.
This use of justify is parallel to Paul’s use in Romans 3:20, 28–30 (and elsewhere):
For by works of the law no human being will be justified [ἐξ ἔργων νόμου οὐ δικαιωθήσεται πᾶσα σὰρξ] in his sight, since through the law comes knowledge of sin. . . . For we hold that one is justified by faith apart from works of the law [δικαιοῦσθαι πίστει ἄνθρωπον χωρὶς ἔργων νόμου]. Or is God the God of Jews only? Is he not the God of Gentiles also? Yes, of Gentiles also, since God is one—who will justify the circumcised by faith and the uncircumcised through faith.
This passage from Clement nicely demonstrates that justification terminology can carry different senses, so it’s not contradictory to insist that a person is justified (sense 1) by works and is not justified (sense 2) by works.