Jesus took great pains to warn the disciples of his impending death. In the book of Matthew to this point Jesus foretells his death on at least three occasions. He was preparing the disciples for what would be a great shock to them and a cause for concern.
Jesus had already warned the disciples of his impending fate in Mathew 16:21-23 when Peter was used by Satan to try and sway Jesus decision. The disciples Peter, James and John also were made aware of Jesus impending death when they were with him at the transfiguration. They heard Jesus discussing his death with Moses and Elijah in Matthew 17:1-8. Then a third time Jesus foretells his death to the disciples in Matthew 17:22-23.
When his death came he did not want the disciples to be unaware of what was going on. He did not want them to be scared or concerned at what was happening. We see he also taught them that it was to their advantage that he died and that it was for this purpose that he came. (John 16:7)
Without the death and resurrection of Jesus there is no New Covenant. For a covenant to be brought into effect there was the requirement for a blood sacrifice. Under the Old Covenant the purpose of the sin offerings were twofold. Their first function was to bring into effect the covenant, and second, to be the offering for the sins of the people.
Jesus’ sacrifice followed this same principle. He died once for all, firstly to bring the New Covenant into force and secondly to be the perfect sacrifice that would enable the removal of sin for mankind.
The disciples were distressed at what Jesus was telling them for they did not understand this yet. They had the Holy Spirit with them, but not in them at this stage. They were still immature in the Lord and needed his guidance and reassurance. However once he had died and been resurrected, and once he had given them the Holy Spirit at Pentecost they understood fully why he had to die and how the New Covenant worked in their lives. They became bold to preach the word of God.
Jesus did not want his death to be a surprise to the disciples. He knew it was for their best that he leaves and he knew also that they would be sorrowful. That is why he spoke to them often about his death and also the suffering that he would go through at the hands of the elders in Jerusalem.
And we should give thanks that he did also. For through his sacrifice we now have the opportunity to be saved from sin and remade into the image of Christ. We are being prepared to receive the gift of glory and eternal life through the death and resurrection of Jesus Christ. Thanks be to his glorious name and the love of both Jesus and the Father towards those who will choose to follow him.