Jesus had just told His disciples to keep on forgiving others who repented of their sins against them - even if they sin and repent seven times a day (Luke 17:4).  The trainee apostles did not think they had enough faith to do that!  So Jesus taught them that faith was not generating the energy to do what might be possible, but achieving the impossible through His command.  The most difficult problem is to see a self-contented person saved into God’s kingdom (Matthew 19:23-26).

He likened faith to a mustard seed - small and insignificant; and likened the intractable problem to a mulberry tree - large with deep roots.  Of course, a mustard seed cannot naturally throw a big tree into the sea, any more than it is naturally possible to restore a relationship which has become entrenched in deep rooted bitterness (Hebrews 12:15).  

But that was Jesus' point.  Faith is not about having confidence in ourselves, or a positive attitude to life.  It is a living relationship with God through Jesus Christ in which we believe that He will give us strength to work with Him through what seem to us to be impossible circumstances - and that He enables the removal of the obstacles (Philippians 4:13).

Our faith does not need to be large, in the sense that we ‘feel’ confident about the future.  Faith only operates when it is placed in the Lord … it is He who does the impossible.  In other words, faith only operates in relationship with the One we trust.  That is: we learn to walk in partnership with God: trusting Him to do all that we cannot, but being willing to work with Him for a common purpose.  In that way, His decisions become our actions and result in wonderful solutions that give Him much Glory.  So, take that impossible matter to Him.  Trust Him that He really does have the power and authority to put everything in its right place, and then take the actions He makes clear to you.  It was to become the daily practice of the apostles as they established the early church under God's hand.  It has been the way of every believer who has made a difference for Christ's sake.  It needs to become your daily way of life too.  Start today!