When was Paul killed? I’ve heard one person say AD 64 and someone else say AD 67. Also why was he killed?
Here is the simple answer. No one knows. There are two general opinions, as you have heard. One is that his imprisonment in Rome, as described by Luke, led to his execution. Those who believe this to be the case will probably give the date of AD 64, as Paul most likely came to Rome in AD 62. Others believe that Paul was released from prison and went to Spain, where he had said he wanted to go. This is the theory of those who propose his death in AD 67. There is indirect evidence that Paul was in fact freed from prison and did visit Spain. First of all, there is his expressed desire to do so in Romans 15:22-29. This, of course, is not very strong evidence. Then there is his expression to Philemon of a rather strong expectation of being released (Philemon 22), as well as a similar expectation of his release in Philippians 1:19-26. Again, this is not strong evidence, and even Paul suggests he was not sure of his release in the Philippians passage. Then there is the evidence of the church historian Eusebius, who said that Paul was not killed due to events described in Acts. But then there is the fact that Eusebius wrote in AD 325.
But there is some stronger evidence that Paul did indeed go to Spain. That is the statement of Clement of Rome, from somewhere between AD 95-100, that Paul went to “the farthest limits of the West” of the Roman Empire (Clement 5:5-7). This statement comes from someone who was most likely alive when this trip to the West was made. It is rather strong evidence that Paul did in fact go to Spain, which would mean that he probably was not executed in AD 64, making the date of AD 67 more likely. It is the universally accepted opinion that Paul was executed in Rome under Nero. Nero died in AD 68, so the date of AD 67 seems fairly likely, but I would not bet on this precise year.
Another thing to bear in mind is that Nero’s horrific persecution of the church in Rome did not happen in AD 64. Here is a likely scenario, but one for which we have scant direct evidence. It is somewhat likely that Paul had returned to Rome after preaching in Spain for whatever reason and that he was caught up in the wave of persecution of Nero against the church there. We can speculate, then, that Nero had Paul executed as the most visible representation of the hated Christian Church. If true, then Paul’s death in AD 67 plus or minus one year, is likely. Might there have been some more immediate reason for Paul being executed? Perhaps, but we simply do not know. What we know from many examples, such as the death of Polycarp, is that Christian leaders tended to be arrested simply for being leaders of the movement, rather than anything specific they said or did. So here is my answer. Paul most likely was executed in AD 67 by Nero as a symbolic act against the leader of the hated cult of Christians in Rome.
For a believer, the exact date of Paul’s death is not important. If it were important, then scripture would record it. What is important is that he spread the gospel through much of the Roman Empire, that he lived a life of incredible commitment and discipleship to Jesus and that he almost certainly received the death of a martyr for his faith.