Go to the Bible and it will become a certainty.
And devout men carried Stephen to his burial, and made great lamentation over him. (Acts 8:2)
Therefore we are buried with him by baptism into death... (Rom 6:4)
So also is the resurrection of the dead. It is sown in corruption; it is raised in incorruption: It is sown in dishonour; it is raised in glory: it is sown in weakness; it is raised in power: It is sown a natural body; it is raised a spiritual body. There is a natural body, and there is a spiritual body. (1 Cor 15:42-44).
Just as seeds are sown into the ground, Christian bodies are "sown" into the ground, to be raised again at the Resurrection Rapture.
BEWARE: CREMATION IS A PAGAN PRACTICE.