And Jesus said unto them, Because of your unbelief: for verily I say unto you, If ye have faith as a grain of mustard seed, ye shall say unto this mountain, Remove hence to yonder place; and it shall remove; and nothing shall be impossible unto you
When the disciples were puzzled about their lack of power, they asked Jesus for an explanation. He gave them a straightforward answer – it was due to their unbelief. If they had the faith the size of a mustard seed, which is the smallest of all seeds, they could command a mountain to be cast into the sea and it would happen. We are to trust God to move mountains, people, or situations, as nothing is impossible with him.