Romans 1:9 μάρτυς γάρ μού ἐστιν ὁ θεός, ᾧ λατρεύω ἐν τῷ πνεύματί μου ἐν τῷ εὐαγγελίῳ τοῦ υἱοῦ αὐτοῦ ὡς ἀδιαλείπτως μνείαν ὑμῶν ποιοῦμαι
For God is my witness, whom I serve in my spirit in the Good News of his Son, how unceasingly I make mention of you always in my prayers,
Noun: Nominative Singular Masculine

Philippians 1:8 μάρτυς γάρ μου ὁ θεός ὡς ἐπιποθῶ πάντας ὑμᾶς ἐν σπλάγχνοις Χριστοῦ Ἰησοῦ.
For God is my witness, how I long after all of you in the tender mercies of Christ Jesus.
Noun: Nominative Singular Masculine

1 Thessalonians 2:5 οὔτε γάρ ποτε ἐν λόγῳ κολακείας ἐγενήθημεν, καθὼς οἴδατε, οὔτε [ἐν] προφάσει πλεονεξίας, θεὸς μάρτυς,
For neither were we at any time found using words of flattery, as you know, nor a cloak of covetousness (God is witness),
Noun: Nominative Singular Masculine

1 Peter 5:1 Πρεσβυτέρους οὖν ἐν ὑμῖν παρακαλῶ ὁ συμπρεσβύτερος καὶ μάρτυς τῶν τοῦ Χριστοῦ παθημάτων, ὁ καὶ τῆς μελλούσης ἀποκαλύπτεσθαι δόξης κοινωνός·
I exhort the elders among you, as a fellow elder, and a witness of the sufferings of Christ, and who will also share in the glory that will be revealed.
Noun: Nominative Singular Masculine

Revelation 1:5 καὶ ἀπὸ Ἰησοῦ Χριστοῦ, ὁ μάρτυς, ὁ πιστός, ὁ πρωτότοκος τῶν νεκρῶν καὶ ὁ ἄρχων τῶν βασιλέων τῆς γῆς. τῷ ἀγαπῶντι ἡμᾶς καὶ λύσαντι ἡμᾶς ἐκ τῶν ἁμαρτιῶν ἡμῶν ἐν τῷ αἵματι αὐτοῦ,
and from Jesus Christ, the faithful witness, the firstborn of the dead, and the ruler of the kings of the earth. To him who loves us, and washed us from our sins by his blood;
Noun: Nominative Singular Masculine

Revelation 2:13 οἶδα ποῦ κατοικεῖς, ὅπου ὁ θρόνος τοῦ Σατανᾶ, καὶ κρατεῖς τὸ ὄνομά μου καὶ οὐκ ἠρνήσω τὴν πίστιν μου καὶ ἐν ταῖς ἡμέραις Ἀντιπᾶς ὁ μάρτυς μου ὁ πιστός μου, ὃς ἀπεκτάνθη παρ' ὑμῖν, ὅπου ὁ Σατανᾶς κατοικεῖ.
"I know your works and where you dwell, where Satan's throne is. You hold firmly to my name, and didn't deny my faith in the days of Antipas my witness, my faithful one, who was killed among you, where Satan dwells.
Noun: 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:
Noun: Nominative Singular Masculine