When the royal official went to see Jesus because his child was dying, Jesus merely spoke and the child was healed.  It didn’t take Jesus to even be there for this miracle to occur.  The miracles Jesus performed could be that easy but he often had to demonstrate the miracle because the faith of His followers was so weak.   For people to believe they had to see it happen.  Obviously the royal official knew that Jesus was special but still, for him to believe, Jesus had to perform a miracle.

John 4:46-54