Jesus saids, "Verily, verily, I say unto you, He that believeth on me, the works that I do shall he do also; and greater works than these shall he do; because I go unto my Father."
The meaning of that is: What I am doing now, whoever believes in me must continue to carry it out. It is because I am leaving!
What were Jesus doing?
Therefore, we will have to continue Jesus' work in order to be a good and faithful servant.
But now people may ask, "I am no Jesus, where comes the power to heal the sick, or to cast out devil?"
Jesus has already given us the answer. He said, "And whatsoever ye shall ask in my name, that will I do, that the Father may be glorified in the Son."
The meaning of this is: When you are continuing my work, whatever you need, just ask (Including the needs to heal the sick and to cast out devil). I WILL do it for you.
NOW I AM HERE TO DO THE GREATER WORKS OF GOD!!!