In Greek, agency – that is, the agent who is doing the action – is often expressed with prepositions. By far, the most common preposition used to denote agency is ὑπὸ (hupo). ὑπὸ typically identifies who is the “ultimate agent.”
Καὶ ἐγένετο ἐν ἐκείναις ταῖς ἡμέραις ἦλθεν Ἰησοῦς ἀπὸ Ναζαρὲτ τῆς Γαλιλαίας καὶ ἐβαπτίσθη εἰς τὸν Ἰορδάνην ὑπὸ Ἰωάννου.
“And it happened in those days that Jesus came from Nazareth of Galilee and was baptized in the Jordan by John.” Mark 1:9
In this passage, John is the agent who is actually doing the baptizing. Therefore, he is the “ultimate agent.” But there are also times when the actions are performed by an intermediate agent. When this occurs, the preposition διὰ (dia) is used.
οἱ δὲ εἶπαν αὐτῷ ἐν Βηθλέεμ τῆς Ἰουδαίας· οὕτως γὰρ γέγραπται διὰ τοῦ προφήτου·
“And they said to him, “In Bethlehem of Judaea: for so it has been written by the prophet.” Matthew 2:5
The prophet referred to in this passage is the prophet, Micah (Micah 5:2). But Micah is only the intermediate agent who spoke the words. Ultimately, the word came from God (the “ultimate agent”), so διὰ is used to denote the intermediate agency of Micah.
Whenever agency is expressed, it’s interesting to see if the agent is considered the intermediate agent or the ultimate agent. Recently, this came to light in my personal reading.
οὐαὶ τῷ κόσμῳ ἀπὸ τῶν σκανδάλων· ἀνάγκη γὰρ ἐλθεῖν τὰ σκάνδαλα, πλὴν οὐαὶ τῷ ἀνθρώπῳ δι' οὗ τὸ σκάνδαλον ἔρχεται.
“Woe unto the world because of offences! for it must needs be that offences come; but woe to that man by whom the offence cometh!” (Matthew 18:7, KJV)
While we live in this cursed world, offence will come. Jesus says it is inevitable. The offences often come by wicked men but we see the men are only considered the “intermediate agents” - διὰ. They may commit the offences, but they are not the source of them. This begs the question: who then is the ultimate agent?
I believe John 8:4 answers this clearly:
“You are of your father the devil, and you want to do the desires of your father. He was a murderer from the beginning, and does not stand in the truth because there is no truth in him. Whenever he speaks a lie, he speaks from his own nature, for he is a liar and the father of lies.”
When we sin, we are only the intermediate agents of sin. The devil is the ultimate agent of sin. Nevertheless, we are not absolved from our actions. Jesus is very clear that we are held accountable. “Woe to the man through whom the offence comes!”