Verbs in English are a bit limited, since they only communicate the action being performed (e.g. "hunting"). More words are needed to be more precise.
For example, to say “I am hunting,” it requires three words (“I” = pronoun; “am” = helping/auxiliary verb; “hunting” = main verbal idea).
In contrast, verbs in Greek are very compact. They communicate a considerable amount of information through a single word.
For example, to communicate the idea of “we are loosing” in Greek, only one word (λύομεν) is required since Greek verbs express both person and number through attached endings (in this example, –ομεν communicates that the verb has a first person plural subject = “we”).
You are already familiar with the concepts of person and number in Greek verbs.
The options for the person of the verb are these: first person (“I” or “we”), second person (“you” [singular or plural]), or third person (“he/she/it” or “they”).
1st person: The subject is speaking.
2nd person: The subject is being spoken to.
3rd person: The subject is being spoken about.
Similarly, number refers to whether there is only one person related to the action of the verb (singular → “I,” “you” sg, or “he/she/it”) or more than one person (plural → “we,” “you” pl, or “they”).
Active: The subject performs the action. E.g. I see.
Middle: The subject both performs and is affected by the action. E.g. I see (for myself).
Middle voice is difficult for English speakers, as there is no equivalent of the Greek middle voice in English. For that reason, it is often translated the same as an active voice verb.
The ancient Greeks thought of some actions as being inherently middle voice. That is, you could not do the action of the verb without affecting yourself. Hence, some verbs such as ἔρχομαι (to come/to go) only exist as middle voice verbs. An active voice version of ἔρχομαι does not exist.Passive: The subject receives the action. E.g. I am seen [by somebody else].
The indicative mood represents something as certain or stated (“He went fishing” or “Will he go fishing?”).
Statements in the indicative mood do not necessarily indicate an objective fact. By using the indicative mood, the author or speaker is choosing to present his speech as factual, at least for consideration. Consequently, it is possible for someone to lie or be mistaken while using the indicative mood.
The subjunctive mood represents something as probable, contingent, or indefinite (“He might go fishing” or “Whenever he goes fishing”).
The optative mood, which is fairly rare in the NT, represents something as possible or hoped for (“I wish he would go fishing”).
The imperative mood represents something as requested or commanded (“Go fishing” or “Please, go fishing”).
New Testament Greek has six tenses: present, future, imperfect, aorist, perfect, and pluperfect. These are sometimes referred to as "tense-forms", since tense (or "time") is not always packaged in the verb.
Here are examples in the active voice and indicative mood.
Present
λύω
“I am loosing” or “I loose”
Imperfect
ἔλυον
“I was loosing”
Future
λύσω
“I will loose”
Aorist
ἔλυσα
“I loosed”
Perfect
λέλυκα
“I have loosed”
Pluperfect
ἐλελύκειν
“I had loosed”
Only in the indicative is there any element of time. In other moods, verbal aspect is totally dominant.
Aspect is a difficult concept for me, as a native-English speaker. I am going to present a slightly different spin on aspect here from the essay I wrote back in 2014 (which is available from the menu to the left under Verbs >> Aspect). There are three kinds of aspect that NT authors have in view.
Imperfective Aspect (present and imperfect tenses): the author depicts the action as ongoing or in process, without attention to the action’s beginning or ending.
Perfective Aspect (aorist tense): the author depicts the action as complete or as a whole. The beginning and ending of the action (and everything in-between) are included in the depiction of the action. The perfective aspect describes a given action simply as occurring or as having occurred without indicating how the action took place (“it happened”).
Stative (or "State-of-being") Aspect (perfect and pluperfect tenses): the author depicts a state of affairs or ongoing relevance resulting from a previous action or state (“it has happened, and it is relevant to the present context”). Depending on the context, there can be more emphasis on the completion of the action or its ongoing relevance.
A good example of the stative aspect would have to do with the resurrection of Jesus. It happened in the past, but has implications for the present.
There is some debate over the significance of the future tense. It generally DOES seem to relate primarily to future time...and is undefined in its aspect.