John 7:28 ἔκραξεν οὖν ἐν τῷ ἱερῷ διδάσκων ὁ Ἰησοῦς καὶ λέγων· κἀμὲ οἴδατε καὶ οἴδατε πόθεν εἰμί· καὶ ἀπ' ἐμαυτοῦ οὐκ ἐλήλυθα, ἀλλ' ἔστιν ἀληθινὸς ὁ πέμψας με, ὃν ὑμεῖς οὐκ οἴδατε·
Jesus therefore cried out in the temple, teaching and saying, "You both know me, and know where I am from. I have not come of myself, but he who sent me is true, whom you don't know.
Adjective: Nominative Singular Masculine

1 John 5:20 οἴδαμεν δὲ ὅτι ὁ υἱὸς τοῦ θεοῦ ἥκει καὶ δέδωκεν ἡμῖν διάνοιαν ἵνα γινώσκομεν / γινώσκωμεν τὸν ἀληθινόν, καὶ ἐσμὲν ἐν τῷ ἀληθινῷ ἐν τῷ υἱῷ αὐτοῦ Ἰησοῦ Χριστῷ. οὗτός ἐστιν ὁ ἀληθινὸς θεὸς καὶ ζωὴ αἰώνιος.
We know that the Son of God has come, and has given us an understanding, that we know him who is true, and we are in him who is true, in his Son Jesus Christ. This is the true God, and eternal life.
Adjective: Nominative Singular Masculine

Revelation 3:7 Καὶ τῷ ἀγγέλῳ τῆς ἐν Φιλαδελφείᾳ ἐκκλησίας γράψον· τάδε λέγει ὁ ἅγιος, ὁ ἀληθινός, ὁ ἔχων τὴν κλεῖν Δαυίδ, ὁ ἀνοίγων καὶ οὐδεὶς κλείσει καὶ κλείων καὶ οὐδεὶς ἀνοίγει·
"To the angel of the assembly in Philadelphia write: "He who is holy, he who is true, he who has the key of David, he who opens and no one can shut, and who shuts and no one opens, says these things:
Adjective: Nominative Singular Masculine

Revelation 3:14 Καὶ τῷ ἀγγέλῳ τῆς ἐν Λαοδικείᾳ ἐκκλησίας γράψον· Τάδε λέγει ὁ ἀμήν, ὁ μάρτυς ὁ πιστὸς καὶ (ὁ) ἀληθινός, ἡ ἀρχὴ τῆς κτίσεως τοῦ θεοῦ
"To the angel of the assembly in Laodicea write: "The Amen, the Faithful and True Witness, the Head of God's creation, says these things:
Adjective: Nominative Singular Masculine

Revelation 6:10 καὶ ἔκραξαν φωνῇ μεγάλῃ λέγοντες, ἕως πότε, ὁ δεσπότης ὁ ἅγιος καὶ ἀληθινός οὐ κρίνεις καὶ ἐκδικεῖς τὸ αἷμα ἡμῶν ἐκ τῶν κατοικούντων ἐπὶ τῆς γῆς;
They cried with a loud voice, saying, "How long, Master, the holy and true, until you judge and avenge our blood on those who dwell on the earth?"
Adjective: Vocative Singular Masculine

Revelation 19:11 Καὶ εἶδον τὸν οὐρανὸν ἠνεῳγμένον, καὶ ἰδοὺ ἵππος λευκός καὶ ὁ καθήμενος ἐπ' αὐτὸν πίστος ⇔ καλούμενος καὶ ἀληθινός καὶ ἐν δικαιοσύνῃ κρίνει καὶ πολεμεῖ.
I saw the heaven opened, and behold, a white horse, and he who sat on it is called Faithful and True. In righteousness he judges and makes war.
Adjective: Nominative Singular Masculine