The key point with the middle voice in Greek is that we don’t have anything equivalent in English. English lumps together actions that are active in Greek with actions that are middle in Greek and generally expresses those actions with the English active voice. This is why we find the middle so hard to wrap our heads around. It’s not a concept we use in our language. So generally, if a verb is middle in Greek it should be translated using the English active voice and you don’t have to worry about the meaning of the middle voice beyond that. (If you’re interested in understanding the meaning of the Greek middle voice, check out my video on the middle here: https://youtu.be/HZ18lHADl-k.)
The trick, really, is that the present tense uses the same forms for middle and passive verbs. How do I know whether the verb ἐρχομαι is middle or passive? It could be either, based just on its form. The key here is that usually the middle voice and passive voice aren’t used with the same verb. Most of the middle verbs you’ll see are middle-only (deponent). The Greeks think of the action of the verb as inherently “middle,” so that it doesn’t make sense to use the active voice with them. This is why the dictionary form is ἐρχομαι, with a middle ending. To remind us that middle-only verbs like this never appear in the active voice.
But if the active voice doesn’t make sense for an action, neither (to the Greeks) does the passive voice. So most middle-only verbs will also never appear in the passive voice. That means in practice ἐρχομαι isn’t really ambiguous. It’s a middle-only verb, so it can’t be passive. The -ομαι ending in this case has to be middle. And, since the middle voice is translated with an English active voice, you should always translate ἐρχομαι with the English active: “I am going.” On the other hand, βλεπω is not a middle-only verb. (You can tell because its dictionary form is active, ending in -ω.) And verbs that can use the active voice usually don’t also use the middle. So if I see βλεπομαι, and I know the verb isn’t middle-only, I’ll assume it’s passive: “I am being seen.”
This is complicated a bit by a few verbs that can appear in either the active or the middle. For practical purposes, you can treat the middle forms of these verbs as a separate meaning of the verb. So ἀρχω means “I rule.” But the middle form ἀρχομαι means “I begin.” Notice that the middle form is still translated with the English active voice. But this isn’t actually a deponent verb because the active voice is also used with this verb. It’s just used to make the verb express a different meaning. With these “middle-sometimes” verbs, you can also have the passive voice used. So ἀρχομαι is ambiguous in the present tense. Is this the middle form meaning “I begin,” or is it the passive form (based on the active-voice meaning of the verb) “I am being ruled”? It could be either. Fortunately, there aren’t very many of these “middle-sometimes” verbs in NT Greek.
Note, too, that since middle-only verbs don’t make sense (to Greeks) in the active voice, they will usually use the middle voice in all verbal moods. So the infinitive of ἐρχομαι is also going to be middle: ἐρχεσθαι. And its imperative will also be middle: ἐρχου. Even its participles will be middle: ἐρχομενος.
All of this gets a little simpler in the aorist tense because you now have different forms for the middle voice and passive voice. That means that the aorist of ἀρχομαι (ἠρξαμην) isn’t ambiguous anymore. It has to be middle, meaning “I began.” Because the aorist passive form would be entirely different, using a different tense marker and set of endings. But everything else stays the same no matter what tense you’re using. Middle-only (deponent) verbs like ἐρχομαι are always middle, never active or passive. (Okay, we’ll see that in a few cases the aorist passive form is used instead of the aorist middle for a deponent verb, but you can ignore that for the moment.) They are going to be aorist middle whether they’re indicative, infinitive, imperative, or a participle. And middle-sometimes verbs like ἀρχω are still going to have different meanings based on whether you use the active or middle voice. That also won’t change, no matter what mood you’re using. So the aorist middle infinitive ἠρξασθαι will mean “to begin,” but the aorist active infinitive ἀρξαι will mean “to rule.” passive form is used instead of the aorist middle for a deponent verb, but you can ignore that for the moment.) They are going to be aorist middle whether they’re indicative, infinitive, imperative, or a participle. And middle-sometimes verbs like ἀρχω are still going to have different meanings based on whether you use the active or middle voice. That also won’t change, no matter what mood you’re using. So the aorist middle infinitive ἠρξασθαι will mean “to begin,” but the aorist active infinitive ἀρξαι will mean “to rule.”
Hopefully this may make the middle voice a bit easier for you to work with in Greek. Again, this discussion is just a starting point. For more check out my related videos: