“By this will we have been sanctified through the offering of the body of Jesus Christ once for all. Every priest stands daily ministering and offering time after time the same sacrifices, which can never take away sins; but He, having offered one sacrifice for sins for all time, sat down at the right hand of God, waiting from that time onward until His enemies be made a footstool for His feet. For by one offering He has perfected for all time those who are sanctified.” – Hebrews 10:10-14
This passage points out how the high priest had to sacrifice day in and day out, and his work was never done. The high priest is viewed as standing to indicate this unfinished ministry. But Jesus, who offered Himself as a sacrifice once and for all, is viewed as sitting at the right hand of God, thus showing that His work is complete. Furthermore, the animal sacrifices provided a yearly atonement but never permanently took away sins. But those who accept the sacrifice of Jesus are perfected forever; their sins are permanently removed.
As to the question, “Why did the Messiah have to die?” the reason is twofold: firstly, to fulfill all Old Testament prophecies such as Isaiah 53 and, secondly, to bring in a permanent atonement rather than a temporary one.
The conclusion of both the Old and New Testaments is that the means of redemption was by blood, and the permanent blood-sacrifice was to be the Messiah Himself. That is why the Messiah had to die according to the Old Testament. That is why Jesus did die according to the New Testament. Who killed Jesus was never the issue as far as the New Testament was concerned, for the Messiah had to die. It only became an issue years later because of anti-Semites seeking excuses to persecute the Jews. The only issue in the New Testament itself is whether or not one will accept the substitutionary sacrifice of Jesus for oneself.
Excerpt from Ariel’s manuscript titled, “Why Did Messiah Have To Die?” A free copy can be downloaded from this link: http://www.arielm.org/dcs/pdf/mbs014m.pdf.