Yes, you need to believe that Jesus rose from the dead. It is one of the essential doctrines of the Christian faith. Paul said in 1 Cor. 15:14, 17, "and if Christ has not been raised, then our preaching is vain, your faith also is vain... 17 and if Christ has not been raised, your faith is worthless; you are still in your sins."
So, according to what Paul the apostle said, if you do not affirm that Jesus has been physically risen from the dead, your faith is in vain; and you are still in your sins. But some may ask whether or not Jesus rose in the same body He died in. The answer is simple. Yes, He rose from the dead in the same body He died in. The Scriptures to demonstrate that are as follows...
- John 2:19-21, "Jesus answered and said to them, “Destroy this temple, and in three days I will raise it up.” 20 The Jews therefore said, “It took forty-six years to build this temple, and will You raise it up in three days?” 21 But He was speaking of the temple of His body."
- Luke 24:39, "See My hands and My feet, that it is I Myself; touch Me and see, for a spirit does not have flesh and bones as you see that I have."
- 1 Cor. 15:42-44, "So also is the resurrection of the dead. It is sown a perishable body, it is raised an imperishable body; 43 it is sown in dishonor, it is raised in glory; it is sown in weakness, it is raised in power; 44 it is sown a natural body, it is raised a spiritual body..."
So we can see that Jesus prophesied that He would raise His physical body. After the resurrection, He said that He had a body of flesh and bones; and according to Paul in 1 Corinthians, the resurrection of Jesus was His body because it says that which is sown in the ground is also that which is raised.
The physical resurrection of Jesus is one of the essential doctrines of the Christian faith, and it is necessary to believe that He rose from the dead.