The sayings found in Matthew’s Mission Discourse here are found in the Eschatological Discourse of Mark (Mk 13,9-13). This is an indication that for Matthew, Mission is already eschatological. The punishment, which is referred to here is not random, but official punishment from members of organised authority. Even in this difficult situation the disciples are offered encouragement. They will depend not on their own strength, but on the Holy Spirit. They are to be missionaries even in the courtroom. Their imprisonment and trial must be regarded as an opportunity to make mission known. Mission takes priority even over family ties and if family ties have to be broken because of mission then so be it. The affirmation of the coming of the Son of Man is probably meant to provide succour to the missionaries in their distress.
Jesus is not calling us here to be sadists and look for suffering, persecution and pain. Rather he is challenging us to go about doing what we have to do, to be as prudent as possible about it and if despite that persecution, suffering and pain come, to be prepared and ready for it and not to be afraid.