Joseph of Arimathea had heard the preaching of Jesus near the beginning when he had traveled through Judea. It was here that he began to hear Jesus' comments about the coming Kingdom of God. His interest was piqued and he continued to follow what Jesus was saying as he traveled. His commitment to the Sanhedrin limited how much he could be present for Jesus' teachings and, yet, he took every opportunity. When approached, Joseph denied any allegiance to this traveling preacher and messiah. He had so much to lose that he didn't think he could afford to follow Jesus openly.
Joseph was probably surprised that Jesus had been arrested. But, he probably expected it, as well, because of some of the challenging and revolutionary things that Jesus was doing and saying in pursuit of the Kingdom of God. Joseph's heart beat faster at the thought that the Kingdom of God might be thwarted by the machinations of mortals. Jesus was condemned to death and crucified by the orders of the Empire and the powers that be. In this, perhaps, Joseph saw the death of the coming Kingdom and wondered if his dreams had met an end on the cross spattered with Jesus' blood.
Out of his grief and desperation, he was moved to go to Pilate and beg for the body of Jesus. When he arrived, Pilate was unsure if Jesus was even dead yet. The centurion informed Pilate that Jesus had died and Pilate, with body to Joseph. He ran and bought fine linen and went to bury the body of Jesus in his own tomb. On his way, he met Nicodemus who brought spices to take part in the burial. It would seem that the death of Jesus had moved both of these two men with much to lose to take a frightening step and demonstrate their allegiance to this now-dead crucified man. It was Jesus' death that finally brought these two men into the Kingdom.
little regard for those who had already died at the hands of Rome, released the
Joseph was a man of great wealth and had a rock-tomb that he had recently had carved for his personal--and preferably eventual--use. They wrapped the body in linen and spice and buried it there in a hurry because of the coming Sabbath. Consider the great number of people who would have watched in surprise as this man of respect and renown traded it all in for the privilege of burying a despised and disreputable man. Though it would have surprised many, it did not surprise Joseph who traded in anything and everything to finally be a citizen of the Kingdom that he had been searching for. Joseph had finally found the door to the Kingdom in the cross and sacrifice of Jesus. Indeed, Joseph found that he couldn't afford not to give all for the Kingdom.