You cannot always work for everything you have. This is what makes a believer clearly different from another human being; that he believes in the supernatural power of God. So he believes that God can do miracles.
The verse teaches us that if we believe on the son of God, not only are we able to do his will but we will do greater things than those.
A child of God has never been called to live a normal life; this is why God allows us to believe for greater works. Some things in this life will only come in one way, the way of the miraculous.
Hallelujah! I believe in miracles because I believe in God. AMEN