“trust like a mustard seed.” This phrase has been mistranslated in a number of versions, resulting in confusion and Jesus giving a teaching contradictory to the context. The context of Jesus’ statement is that Jesus’ disciples were not able to cast a demon out of a boy (Matt. 17:16) and wanted to know why (Matt. 17:19). Jesus told them it was because of their little trust (Matt. 17:20). At that point the Greek text says: “If you have trust [faith] like a mustard seed….” How much trust does a mustard seed have? Total trust! It may look small to the world, but it has no doubt that it can do what God created it to do and become the largest garden herb. That is the point Jesus is trying to make. It does not matter what he, or his disciples, looked like to the world, if they have the same kind of total trust that a mustard seed does, they could move mountains.
Unfortunately many translations entirely miss the point that Jesus was making. For example, the NIV84 has Jesus saying, “…if you have faith as small as a mustard seed….” But they added the word “small,” which is not in the Greek text, and that added word completely turns the parable upside down. Other versions that add words about the size of the mustard seed include the HCSB, NET, and NRSV. The problem the disciples had was that their trust was too small for them to cast out the demon. So Jesus is not saying if they had small faith they could move mountains—that is the opposite of what he is saying! Small faith won’t cast out demons or move mountains. But total trust, like the tiny mustard seed has in its ability to grow into a huge plant, will cast out demons and move mountains.