Cody, the Abel–Zechariah saying is worth a deeper look. It seems to me that Jesus’ choice of these two names points to a literary reference (to characters in literature rather than actual people in time), and his description of Abel as a prophet suggests Jesus sees special importance in the figurative statements in Genesis.
Here is Luke’s version of the saying:
Woe to you, because you build tombs for the prophets, and it was your ancestors who killed them. So you testify that you approve of what your ancestors did; they killed the prophets, and you build their tombs. Because of this, God in his wisdom said, “I will send them prophets and apostles, some of whom they will kill and others they will persecute.” Therefore this generation will be held responsible for the blood of all the prophets that has been shed since the beginning of the world, from the blood of Abel to the blood of Zechariah, who was killed between the altar and the sanctuary. Yes, I tell you, this generation will be held responsible for it all. (Luke 11:47–51, NIV)
Which Zechariah is it? In 2 Chronicles 24, a priest–prophet named Zechariah is murdered in the temple court. This matches well with Luke’s version, but Matthew includes an extra detail: Zechariah is the son of Barachiah. This suggests the minor prophet with that name (see Zechariah 1:1). The trouble is there is no mention of how or where this Zechariah died, yet both Matthew and Luke specify a Zechariah killed in the temple.
The language of “son of” can simply mean “descendant of,” so it’s possible a Barachiah is somewhere in the list of ancestors of the Zechariah killed in 2 Chronicles 24. It’s also possible that the minor prophet Zechariah was killed in the (later) temple as well. Either way, one has to speculate about details not in the text (either that, or perhaps Matthew or someone else simply made a mistake in adding the name Barachiah). The connection with the Zechariah killed in 2 Chronicles 24 seems most plausible, and virtually certain for Luke’s version that doesn’t include the name Barachiah.
How are Abel and Zechariah extremities? In English, this seems to be the A–Z of murders, but that doesn’t work in Greek since the letter omega ends the alphabet, not zeta. So how is Abel the first and Zechariah the last? Abel can easily be read as the earliest one killed, but Zechariah doesn’t work as the most recent killed prophet. A few chapters earlier, Luke speaks of how John the Baptist – a clear prophet – was beheaded (9:9). Since neither John nor some other more recently-killed person is mentioned, the focus can’t be strictly chronological.
Most likely is that Abel is the first murder and Zechariah the last in the Hebrew Scriptures. In the Hebrew canon, the last book is 1–2 Chronicles. The last clear murder of a prophet in that book is of Zechariah in 2 Chronicles 24:20–22. The focus is on what is written and in what order it appears, not on history and chronology.
How is Abel a prophet? In Genesis, Abel never speaks. His very name means “vapour” (it’s the word translated “vanity” or “meaningless” in Ecclesiastes), and Genesis underscores how he’s snuffed out and replaced by Seth (4:25). Aside from the effects on Cain, it’s like he never existed. He’s never called a prophet elsewhere.
But though in life we have no record of his speech, in death his blood cries out (4:10)! Abel is a prophet due to a figure of speech in Genesis. Jesus takes the story in Genesis so seriously that even the clearly figurative parts matter. Since Abel’s blood speaks to God in Genesis, Jesus calls Abel a prophet – the first murdered prophet in the Scriptures.
Anyway, I don’t see anything in this saying that suggests Jesus is emphasizing (or rejecting) the historical reality of Abel. That’s completely beside the point. Jesus’ saying requires his audience to have familiarity with the Hebrew Scriptures, not with some gapless history of every prophet ever killed. They need to know the literary Abel – the Abel who is a prophet because, as the story is told, his shed blood cried out to God. What they know or believe about Abel’s historicity doesn’t matter.