James 5,15 identifies the prayer with faith. One prayer of faith achieves more than many years of prayer without it. Sadly, our faith is generally rather poor.
We cannot expect to receive unless we believe, and Jesus taught us, in Mark 11:24, to believe that we have received when we pray. This is the prayer of faith. James 1:6-8 helps us to understand what this means in practice. There are two major questions about believing in God: 1. Is he able? 2. Is he willing?
In Mark 9:14-29, Jesus’ ability was brought into question because the disciples had been unable to heal a young boy with a mute spirit. But there is never anything wrong with God’s power – only with our unbelief.
Mark 1:40-45 deals with God’s willingness to bless. Many people who are struggling with hurt and disappointment blame God as unwilling. Like the leper, they say: ‘You could help me if only you were willing.’ But Jesus’ response in Mark 1:41 [read the verse] settles the matter.
This is our challenge today. We must believe him and, by our prayer of faith, demonstrate that he is both willing and able to answer in time of need. (From Colin Dye, Effective Prayer, London 2007, pp. 135-136)