Most Greek verbs are in the active voice in the New Testament. But certainly not all of them. That's why I am eager to introduce to my students -- for the first time! -- the middle and passive voices today.
In essence, these voices call attention to the grammatical subject of the sentence. This is why I have a problem with how the GNT renders Matt. 5:4:
"Happy are those who mourn; God will comfort them!"
This statement is undoubtedly true. But Matthew uses the passive voice here, not the active. Here's the ESV:
"Blessed are those who mourn, for they shall be comforted."
The idea is: THEY will be comforted. They of all people! In fact, the Greek adds the word "themselves" to make sure we get the idea. Hence the ISV's:
"How blessed are those who mourn, for it is they who will be comforted!"
Grief in life is inevitable, but it's not inevitable that we go through it alone. What an incredible truth!