First, the apostles were continually threatened and pressured to deny their Lord during their ministry; especially as they faced torture and martyrdom. However, none of these men who spent time with Jesus chose to save their lives by denying their faith in Him.
Consider this hypothetical situation: Suppose these men had conspired to form a new religion based on their imagination. How long would anyone continue to proclaim something they knew was a lie when faced with lengthy tortures and an inescapable, painful death? All they had to do to escape martyrdom was to admit they had concocted a lie and simply deny their faith and claims about Jesus as God. It defies both common sense and the evidence of history that anyone, let alone a group of twelve men, would persist in proclaiming a lie when they could walk away by admitting that it was a fraud.
Yet, history reveals that not one of these men, who knew Jesus personally, ever denied their testimony about Him despite the threat and reality of imminent death. This proves to any fair-minded observer that these men possessed an absolute unshakable personal knowledge about the truth of the life, death, and resurrection of Jesus. Each of the apostles were called upon to pay the ultimate price to prove their faith in Jesus, affirming with their life's blood that Jesus was the true Messiah, the Son of God, and the only hope of salvation for a sinful humanity.
Reference for above: Jeffrey, Grant R., "The Signature of God", Frontier Research Publications, Inc. (1996), p.254-257
Most of our information about the deaths of the apostles is derived from early church traditions. While tradition is unreliable as to small details, it very seldom contains outright inventions. Eusebius one of the most important of the early church historians wrote his history of the early church.
Matthew suffered martyrdom in Ethiopia, killed by a sword wound.
Mark died in Alexandria, Egypt, after being dragged by horses through the streets until he was dead.
Luke was hanged in Greece as a result of his tremendous preaching to the lost.
John faced martyrdom when he was boiled in a huge basin of boiling oil during a wave of persecution in Rome. However, he was miraculously delivered from death. John was then sentenced to the mines on the prison island of Patmos. He wrote his prophetic Book of Revelation on Patmos. The apostle John was later freed and returned to serve as Bishop of Edessa in modern Turkey. He died as an old man, the only apostle to die peacefully.
Peter was crucified upside down on an x-shaped cross, according to church tradition because he told his tormentors that he felt unworthy to die in the same way that Jesus Christ had died.
James the Just, the leader of the church in Jerusalem, was thrown over a hundred feet down from the southeast pinnacle of the Temple when he refused to deny his faith in Christ. When they discovered that he survived the fall, his enemies beat James to death with a fuller's club. This was the same pinnacle where Satan had taken Jesus during the Temptation.
Church tradition says that James, brother of Jesus, wrote the book of James in the New Testament, although the author assignation in James 1:1 is ambiguous. (One of several places in the New Testament where it is difficult to ascertain which “James” is being referenced! – see also 1 Cor 15:7). James is mentioned by Josephus in his massive work Jewish Antiquities.
James the Greater, a son of Zebedee, was a fisherman by trade when Jesus called him to a lifetime of ministry. As a strong leader of the church, James was ultimately beheaded at Jerusalem. The Roman officer who guarded James watched amazed as James defended his faith at his trial. Later, the officer walked beside James to the place of execution. Overcome by conviction, he declared his new faith to the judge and knelt beside James to accept beheading as a Christian.
Bartholomew, also known as Nathanal, was a missionary to Asia. He witnessed to our Lord in present day Turkey. Bartholomew was martyred for his preaching in Armenia when he was believed to have been flayed to death by a whip. He may have also been crucified.
Andrew was crucified on an x-shaped cross in Patras, Greece. After being whipped severely by seven soldiers they tied his body to the cross with cords to prolong his agony. His followers reported that, when he was led toward the cross, Andrew saluted it in these words: "I have long desired and expected this happy hour. The cross has been consecrated by the body of Christ hanging on it." He continued to preach to his tormentors for two days until he expired.
Thomas was stabbed with a spear in India during one of his missionary trips to establish the church in the subcontinent.
Jude, the brother of Jesus, was killed with arrows when he refused to deny his faith in Christ.
Matthias, Matthias was chosen by the Apostles to replace Judas Iscariot, after the death of Judas in the Field of Blood. Information concerning the life and death of Matthias is vague and contradictory. One tradition maintains that Matthias was stoned at Jerusalem by the Jews, and then beheaded. (cf. Tillemont, "Mémoires pour servir à l'histoire eccl. des six premiers siècles", I, 406-7).
Barnabas, one of the group of seventy disciples, wrote the Epistle of Barnabas. He preached throughout Italy and Cyprus. Barnabas was stoned to death at Salonica.
Phillip was crucified, according to the plaque in the church of the Holy Apostles.
Paul was believed to have been tortured and then beheaded by the evil Emperor Nero at Rome in A.D. 67. Paul endured a lengthy imprisonment which allowed him to write his many epistles to the churches he had formed throughout the Roman Empire. These letters, which taught many of the foundational doctrines of Christianity, form a large portion of the New Testament. Most scholars believed that Paul was released from house arrest in Rome in c. 62 A.D., and that he may have made a fourth missionary journey, which may have gone as far as Spain (Rom 15:24, 28). Church tradition says that Nero executed Paul in Rome c. 67 A.D. (see “Church Tradition” section below). However, the New Testament is silent on the death of this great apostle.
The details of the martyrdoms of the disciples and apostles are found in traditional early church sources. These traditions were recounted in the writings of the church fathers and the first official church historian Eusebius. Although we can not at this time verify every detail historically, the universal belief of the early Christian writers was that each of the apostles had faced martyrdom faithfully without denying their faith in the resurrection of Jesus Christ.
Also. See the life and death of Saint Mark (the evangelist) here
Read the early Christian apocryphal writings about the Apostles
These were strongly held by early Christians to be authentic stories of the apostles, their ministries, their miracles, and their deaths. Among the reasons it was believed that these writings were not canonized into Holy Scripture is that among those who strongly believed these writings there were many heretics. These are awesome, however. Read here....
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