a note on the translation: ἐμέσαι

you would spit out a venom but you would spew something out which you had first eaten or had drunk. And you would spit something out of your mouth before you had eaten or had drunk it. But you would try to spew something out which had been or had grown inside you, like a disease or a parasite.

Revelation 3:16 allows for a compromise by having ἐκ τοῦ στόματός μου – literally “out of the mouth of me” – out of my mouth. Also, ἐμέσαι is preceded by μέλλω σε – the latter in English: “I am about to” – I am about to spit/spew you out of my mouth. However, ἐμέσαι contains the root for emetic, so the phrase τινα ἐκ τοῦ στόματος could be translated as “reject with extreme disgust” – Thus because you are lukewarm and neither hot nor cold I’m going to reject you with extreme disgust.

Choosing among rejecting with extreme disgust, spewing or spitting may be less important than the elision or inclusion of the word indicating my present intention: I am going to – present indicative, first person singular – μέλλω. I haven’t yet, but I am going to, I’m going to try to spew you out, to reject you with all the force of my disaffection: You are abject.

And so because you are lukewarm and neither warm nor cool I’m going to vomit you out of my mouth.