Let's first consider who Jesus is speaking to: Then Jesus said to the crowds and to his disciples. (Matt. 23:1) Among the crowds were Jewish priests and pharisees, some who had questioned Jesus. Jesus then proceeded to focus his discussion upon these high priests and pharisees of the ecclesiastical Jewish temple of that time (see previous verses).
Jesus says he will be "sending you prophets and wise men and teachers." Who are these? These are his disciples:
These twelve Jesus sent out with the following instructions: "Do not go among the Gentiles or enter any town of the Samaritans. Go rather to the lost sheep of Israel. As you go, preach this message: 'The kingdom of heaven is near.'" (Matt. 10:5-7)But Jesus did not simply send twelve:
After this the Lord appointed seventy-two others and sent them two by two ahead of him to every town and place where he was about to go. (Luke 10:1)And he instructed them to pass on his teachings:
"Heal the sick who are there and tell them, 'The kingdom of God has come near to you.'" (Luke 10:9)So Jesus is explaining that he is sending out his students to pass on his teachings to others. This is the ancient process of passing on God's message. The devoted student learns from a spiritual teacher who was a devoted student of a spiritual teacher who was a devoted student of a spiritual teacher and so on. Each becomes committed to the teachings of their teacher, and establishes their own relationship with God. After such time, they may be empowered by God to teach to others.
This is why Jesus became baptized by John the Baptist, and why Jesus also took on his own students. This is also why Samuel was a student of Eli and David was a student of Samuel, and Solomon was a student of David and so on. The Old Testament, in fact, was intended (before being mistranslated by ecclesiastical interpreters) to be a chronology of a particular line of teachers and their students.
Note also in Jesus' statement that he recognizes some of his students will be tortured and killed. This did take place. Not only in the case of Peter - who was crucified upside down - but others who were not so famous.
In the decades following Jesus' passing came the Roman-Jewish wars. These lasted nearly a century. For decades, the entire society was in crisis. Romans were burning down Jewish settlements, and killing both Jews and Christians. This was a very dark time in human history. There was such turmoil, that Jewish people were trying to pretend to be Romans, and trying to gain kudos from other Romans by turning in other Jews - sometimes even their own family members.
During this time, as far as the Romans were concerned, there was little or no difference between those Jews who were following the teachings of Jesus - considered a Jewish rabbi - and those who were not. They were all considered Jews to the Romans. Thus the Romans were killing all types of Jews, and the Jews were also turning on themselves. And those Roman Jews who worked for the Romans in their official posts were persecuting those Jews who were teaching and/or following the teachings of Jesus.
In Matt. 23:34-36 Jesus is foretelling this persecution of both his followers and the Jews in general. Notice his last sentence here says "all this will come upon this generation." By generation, he means those during the lives of those around him. "Generation" here is being translated from the Greek word γενεά (genea) which indicates, from the Greek lexicon, "an age (i.e. the time ordinarily occupied be each successive generation), a space of 30 - 33 years," as well as "the several ranks of natural descent, the successive members of a genealogy." So the implication is that Jesus is foretelling of events that would take place in the coming decades, to those of that generation of Jews - making up the bulk of the crowd Jesus is speaking to.
Jesus is also speaking of previous messengers of God who were murdered. Abel and Zechariah were both loving servants of God. In the case of Abel, he was murdered by Cain. In the case of Zechariah, there is some controversy about "Zechariah son of Berekiah" and his being killed "between the temple and the altar." The Infancy Gospel of James, a Gnostic text from the second century, appears to identify this Zechariah with John the Baptist's teacher, the priest, Zechariah, who was murdered by Herod's agents in a temple yard. However, this Zechariah was not the son of Berekiah, and there is no clarity that this Zechariah was murdered in such a way from scripture. Some have speculated that Jesus was speaking of Zechariah son of Jehoiada from Chronicles 2, who was stoned in the courtyard "of the Lord's temple" for opposing idol worship.
But does it matter? We know at least two Zechariahs were murdered for their devotion to God. Why does it matter which one? Is two murders of God's devoted teachers not enough?
The bottom line is that Jesus is speaking of a culture and a society that has turned their backs on the Supreme Being. They were a self-serving society. The anger we find in Jesus' statements against these people was also found repeatedly in the Old Testament as God relayed His disappointment and upset with the Israelites. Why?
It is about love. Those who came to teach the Israelites about God were God's loving servants. They were lovingly devoted to God. And those who were focused upon retaining their power and authority - being threatened by God's power and the teachings of God's loving servants - tortured and murdered those loving servants. Just imagine how upset you would be if you sent someone to help a group of people and they murdered the person you sent.
Jesus also relays this mood within his parable of the wedding banquet:
"The kingdom of heaven is like a king who prepared a wedding banquet for his son. He sent his servants to those who had been invited to the banquet to tell them to come, but they refused to come. Then he sent some more servants and said, 'Tell those who have been invited that I have prepared my dinner: My oxen and fattened cattle have been butchered, and everything is ready. Come to the wedding banquet.' But they paid no attention and went off - one to his field, another to his business. The rest seized his servants, mistreated them and killed them. The king was enraged. He sent his army and destroyed those murderers and burned their city. Then he said to his servants, 'The wedding banquet is ready, but those I invited did not deserve to come. Go to the street corners and invite to the banquet anyone you find.'" (Matt 22:2-9)There is more to this parable, but the meaning of this section is critical to the position that God has been in with regard to those loving servants that He has consistently sent to the earth to bring us back to Him.
Consider first what kind of anger this is. This is not the kind of anger we experience when we become upset at someone who doesn't do what we want them to do. This is anger that is related to loving someone.
First, God enjoys a loving relationship with those who He has sent to bring us home. To see His loving servants suffer makes Him angry due to His love for them.
Second, God - also out of love for us - wants us to regain the loving relationships we shared with Him prior to the point we rejected Him and we fell into the physical universe and took on these temporary physical bodies.
God, out of His love, is trying to bring us back to Him by sending His loving servants to canvas us. So God also becomes sad and angry - again out of love - when we reject those attempts and decide to continue on our self-centered ways.
This kind of anger would compare to a parent becoming angry at their child after the child runs off and steals candy form a store. They are not angry about the candy or the store. They are angry because they know that stealing is not good for the child. A criminal life is an awful life, and the parent does not want to see their child suffer like this. So their anger is out of love for the child.
In the same way, God becomes angry out of love. While many might doubt that God is a loving God because He gets angry, the type of anger that God has - and Jesus shows here as well - is actually love. Their anger is out of love for us.
These bodies are temporary and virtual. They are not our true identity. If our body gets hurt or dies, we don't die. Just as a driver gets in a car and drives it, the living spiritual individual gets into a physical body and drives it for 50-100 years. The body then falls apart or gets killed and the spiritual individual leaves the body. Therefore, the spiritual individual is separate from the physical body. Just as the driver can step out of the car when the car breaks down, the spiritual individual leaves the body at the time of death.
Therefore, we must remember that those events that take place to our bodies do not happen to us. Just as our game avatar or icon in a computer game can get punched and blown up without affecting the person sitting at the computer operating the controls, the physical body can undergo all sorts of calamities without touching the spiritual individual. The spiritual individual will remain untouched - outside of the lessons the physical events convey. But even this is similar to the virtual computer game. The computer operator might not be affected by his avatar getting blown up, but he will learn lessons from the game. He'll come to understand why the avatar got blown up and any other lessons the game was designed to teach us.
We could also compare this to parental discipline. The child might be really upset that she got sent to her room, but the parent knows this is a passing thing. The main thing the parent is concerned about is the long-term education of the child.
In the same way, God set this physical world up to teach us. The primary lessons being taught in the physical world relate to love. They relate to how we treat others and how we care about others. When we treat others badly, we get treated badly. Why? Because God designed the physical world to steer us towards our natural position - of loving and caring about others. We get treated badly after we treat others badly so that we will understand how it feels.
Understanding how it feels to be someone else is also called empathy. Once we develop empathy, we can begin to care for others.
Learning to care for others is part of the journey towards re-developing our innate love for the Supreme Being. And once we are re-introduced to God by one who already loves Him, we can come to know God and learn to love God. Then we can truly love others. This is why the Supreme Being periodically sends His loving servants to teach us. This is also why Jesus said:
“ ‘Love the Lord your God with all your heart and with all your soul and with all your mind.' This is the first and greatest commandment.” And the second is like it: ‘Love your neighbor as yourself.’ All the Law and the Prophets hang on these two commandments.” (Matt. 22:37-40)
(For a translation of Jesus' statements from the Book of Matthew without institutional sectarian influence, see the Gospels of Jesus - translated from the original Greek texts.)