As Travis pointed out, this is a natural belief. Jesus is God, the Son. He is as His Father. He became "man," died, and lives. He appeared to His Disciples with a body.  
The question we might ask is: where do we get the idea that He died again, or got rid of His body after dying once for sins? 
Well that's a long story... briefly told: before Jesus established His Church, before He was born even, the learned people of the times were educated in Greek Philosophy. Some thought God was one of Plato's ideal Forms. They had the idea that bodies, and anything physical, were evil, or less than good. After the apostles were killed, these ideas, this science of the times, crept in, and caused contention.  
Some of the creeds were written to synthesize, and perhaps in hopes pf making peace some conformed faith to the same science that taught that the world was at the center of the universe.