In the active voice the subject is represented as producing that action, or in the case of a linking verb, as existing
The Simple Active
The subject directly performs the action or just simply exists.
The Causative Active
The active does not produce the action, but rather causes it to take place.
The basic significance of the middle voice is that it represents the subject as acting with reference to itself in some way. Therefore, there is a special emphasis on the subject. The middle is strictly speaking, never used without some sort of reference to the subject.
The Direct Middle
This use is sometimes referred to as the “reflexive Middle.” The results of the action are directly referred to the subject.
The Indirect Middle
This use of the middle portrays the subject as producing the action rather than participating in the results. The subject acts for itself.
The Permissive Middle
This use denotes the subject as having someone else do something for him, or letting someone else do something to him.
The Reciprocal Middle
The middle reflects an interchange of action between or among members of a plural subject. The subject is always in the plural.
The passive voice represents the subject as being acted upon by someone or something outside of itself. Therefore, the subject is the recipient of the verbal idea.
The Passive with a Direct Agent
When the original or direct agent of the action being produced in a passive verb is indicated, the normal construction if ὑπό with the ablative.
The Passive with an Intermediate Agent
When the action expressed by a passive verb is performed on behalf of another, the agent performing the action is the intermediate agent or medium, the usual construction is δια with the genitive.
The Passive with an Impersonal Agent
When the agent, through which the action is produced, is an impersonal or inanimate thing, the usual construction is the instrumental case, with or without the preposition εν.
The Passive with no Agent
The passive was used in order to avoid directly naming God as the agent. This is referred to as the “Theological Passive.”