Thank you for the question about the Second Coming of Christ.
Here are some thoughts why John of Patmos doesn’t contradict the words in Matthew 24:36:
A. John of Patmos recorded the vision that was revealed to him by the resurrected Jesus. The vision didn’t originate with him.
B. The recorded vision was an expansion or clarification of what Jesus spoke in Matthew 24–25.
C. John of Patmos didn’t record the date and time of Jesus’ return. John doesn’t give a specific date but the circumstances that will lead to Jesus’ return.
D. The words of Jesus in Matt. 24–25 and the vision given to John were to remind the believers of his return.
Summary: Jesus didn’t contradict his own words to the disciples in Matthew 24–25 or in the revelation to John of Patmos. They are complementary.
For more perspectives: