The story of the boy with the spirit is an interesting one. The father brings the boy for healing, and the disciples pray but with no success. Jesus returns and is able to cast the spirit out ... leading to lots of questions for the disciples, and for us too!
Between the three gospel accounts (Matthew, Mark and Luke) we see references to unbelief and the need for prayer (plus fasting in some manuscripts). The need for prayer and fasting reminds us that intimacy with Jesus is crucial - we cannot expect prayer for healing (or any other prayer) to be a slot machine. Our recommended habit of being 'ever closer to Jesus' reflects this - let us strive to be closer to Him, spending time, becoming more like Him.
The talk of unbelief is trickier. For a start, whose unbelief? I would suggest not the father bringing the boy - Jesus never seems to directly criticise the faith in someone coming before him in desperation.
The teachers of the law? Yes - the gospels overall portray a tussle between Jesus with His announcement of the Kingdom of God and unbelieving religious teachers and priests.
The general crowd? Quite possibly - there does seem genuine frustration for Jesus at the lack of faith in some places.
The disciples? Yikes, because that could include us! Curiously these same disciples had been commissioned and sent out (Mark 6) where they had seen success, so why the apparent failure now? Jesus comments on faith as small as a mustard seed - was their faith now even less than that? Perhaps the disciples fell into the trap of simply reflecting a general unbelief around them, rather than standing in contrast with a living faith in Jesus.
The ensuing discussion shows this as another teaching moment. As before with the Canaanite Woman, each incident with Jesus can be a teaching episode. Jesus is able and willing to heal, perhaps the block lies more with us? For faith is not simply an intellectual agreement, but something to be lived. In the heat of a moment, no matter how horrible and desperate it may look, we should still look to Jesus in a simple reliance of his ability to act.
Jesus' question 'how long ...' may stem from frustration with people who still didn't get it, but it may also be stating the reality that soon Jesus will not physically be present, so the disciples must learn to minister without him around. That of course applies to us too, so let us examine our own faith ministry and ask:
Key Qn: [OUT] Where are you called to exercise faith in Jesus?
Challenge: Offer to pray in name of 'Jesus who heals'
When we offer to pray we cannot of course guarantee healing, but we can still humbly offer to pray knowing that Jesus can and does heal today.
The disciples were called to do as Jesus did ... and so are we. Although Jesus would not physically be present, he was not going to leave them (or us) as orphans. Instead he will empower with the Spirit who will be present with us ...