Verse 16:[1] Repent; or else I will come unto thee quickly, and (Is. 11:4; 2 Thess. 2:8; Rev. 1:16; 19:15, 21) will fight against them with the sword of my mouth.
[Repent] That is, correct the error (Piscator). Be thou not so remiss afterwards: make use of sharper remedies, as thou dost in grave danger (Grotius). The Nicolaitans, therefore, appear openly, with the Bishop indulging, to have had intercourse, and to have performed nefarious rites with a tempting of the faithful (Pareus).
[But if not] That is, If thou doest it not (Grotius).
[I will come to thee] So that I might punish thee on account of thy negligence (Ribera). The same expression as is in Revelation 2:5 (Grotius).
Repent; thou that art guilty of conniving at such things, change thy mind and practice, and let those who have entertained these opinions, and run into those filthy practices, change their hearts and practices; or else I will come unto thee quickly; I will quickly come against thee, and punish thee: see the notes on Revelation 2:5.
[And I will fight with them (that is, thine that follow that doctrine [Ribera]: both with thee, and with them [Tirinus, similarly Pareus]) with the sword of my mouth] By threatening and imposing punishments (Pareus), by speaking a sentence of death against them (Menochius, Tirinus), and by inflicting it (Menochius); by convicting and condemning them (Pareus): even by my word, which all by itself is sufficient to destroy all the impious (Gagnæus). I will rouse Prophets in the Church that will do that which the Bishop neglects, and they will oppose the Nicolaitans and draw the people from them. Christ is said to do what He does through His Prophets, as God is said to fight, when Israel fights, Exodus 14:14, 25; Deuteronomy 1:30; 3:22; Joshua 10:42; 23:3; 2 Chronicles 20:15 (Grotius). It is an allusion to the ancient history. For both Balaam and his counsel were destroyed by the sword of the pursuing Israelite, Numbers 25:5; 31:8 (Grotius, similarly Ribera).
And will fight against them with the sword of my mouth; and fight against them by my word; either convincing them, or pronouncing sentence against them; or, by raising up other teachers, who shall preach my word more faithfully, and whose doctrine shall be like a sword to devour and to destroy them.
[1] Greek: μετανόησον· εἰ δὲ μή, ἔρχομαί σοι ταχύ, καὶ πολεμήσω μετ᾽ αὐτῶν ἐν τῇ ῥομφαίᾳ τοῦ στόματός μου.