A study of martyrdom and the martyrs: The mind set that clamored, "Kill the infidel!"; The Protomartyr; Nero's Pogrom; Individual martyrs; Wholesale Persecutions; Lawrence; A Martyr's Rationale.
There is a saying that the blood of martyrs is the seed of Christians, that those who gave their lives for Christ would, by their faith and constancy, win many converts. The first converts and the first martyrs were Jews. Jesus said, “I was not sent except to the lost sheep of the house of Israel,” (Matt. 15:24) and the apostles continued this work. Their success, their witness and their persecution are detailed in The Acts of the Apostles.
To understand why the disciples of Jesus were persecuted, you must refer to the Gospels. There you will find Jesus revealing to his disciples, and then publicly confronting his enemies with, his divine identity.
Now Jesus, having come into the district of Caesarea Philippi, began to ask his disciples, saying, “Who do men say the Son of Man is?” But they said, “Some say, John the Baptist; and others, Elias; and others, Jeremias, or one of the prophets.” He said to them, “But who do you say that I am?” Simon Peter answered and said, “Thou art the Christ, the Son of the living God.” Then Jesus answered and said, “Blessed art thou, Simon Bar-Jona, for flesh and blood has not revealed this to thee but my Father in heaven.” (Matt. 16:13-17)

When confronting his enemies, he says,
“Abraham your father rejoiced that he was to see my day. He saw it and was glad.” The [Jewish leaders] therefore said to him, “Thou art not yet fifty years old, and hast thou seen Abraham?” Jesus said to them, “Amen, amen I say to you, before Abraham came to be, I am.”The great I AM, the name reserved to God alone. What was the reaction?
They therefore took up stones to cast at him; but Jesus hid himself and went out from the temple. (John 8:56-60)This was the basis of officialdom’s resistance to Christ: that he committed blasphemy in making himself God. (c.f. Matt. 26:63-67)
The Jews at this time had long been a subject nation, fighting to keep their identity, their culture and the people’s allegiance to the unseen God. Under the Greeks they had already suffered the horror of seeing a Greek god enthroned in the temple's holy of holies. (1 Mach. 1:57) False Messiahs arose from time to time and attracted a following which dispersed when their leader died. Gameliel drew on this experience when advising the Sanhedrin to wait and see what happened to the followers of Jesus. (Acts 5:34-40) It was essential that no change be made to the concept of God as it was handed down from their forefathers and interpreted by the Pharisees. The good of the Jewish nation depended upon their worship of a God who was pure spirit, and any man who claimed to be God and taught heretical concepts must be stopped. Yet, in connecting their security as a people with their worship of their God, the Jews shared a particular mindset with Greeks, Romans, and all other ancient peoples.
Although the Jews practiced a revealed religion and the pagans struggled to appease or gain the favor of natural forces they had personified and deified, both believed the fate of the nation depended upon their worship of their god. The gods were the soul of the nation, their distinctive character and source of unity. Upon subduing a state, the Romans placed its god within the Roman pantheon to ensure the unity of the empire. The concept of Individualism developed later; the individual in ancient times was identified by his place within the group, (See Endnote 1) and the group depended upon its god. If they won a battle, it was their god who was victorious; if they lost the battle, it was because their god had deserted them. (See Endnote 2). In the time of the Roman republic, a senator was convicted of treason and executed because he gave the names of the Roman gods to the enemy, thus giving them control of the republic. After centuries of fighting alien cultures, of seeing their people sometimes converting to the worship of idols, the orthodox Jewish teachers could never tolerate a man setting himself up as worthy of adoration.
ENDNOTES
1. The greatest punishment the Greeks could inflict was to ostracize a person. He was cast out from his family, from his work, from his friends. All turned their backs to him as he left the city. He was now a nonentity, a non-person. Many ostracized souls committed suicide.
2. In settled, agricultural times the god also embodied the land, just as the people themselves felt a oneness with the land. It took a nomad like Abram to accept the existence of a God who was everywhere and nowhere, omnipresent yet not confined in any object.