Context is everything.  The context of a faith and prayer that moves mountains (Mk 11:22-25) is about prayer offered from a forgiving heart.  “And whenever you stand praying, if you have anything against anyone, forgive him, that your Father in heaven may also forgive you your trespasses” (Mk 11:25).  It is impossible to move the mountains around us until we have removed the mountain of un-forgiveness within us.  It matters to prayer.  It matters to faith.