Jesus taught His disciples how to increase this kind of faith.
Luke 17:5 The apostles said to the Lord, “Increase our faith!”
6 He replied, “If you have faith as a mustard seed, you can say to this mulberry tree, ‘Be uprooted and planted in the sea,’ and it will obey you.
7 “Suppose one of you had a servant plowing or looking after the sheep. Would he say to the servant when he comes in from the field, ‘Come along now and sit down to eat’? 8 Would he not rather say, ‘Prepare my supper, get yourself ready and wait on me while I eat and drink; after that you may eat and drink’? 9 Would he thank the servant because he did what he was told to do?
The point of this parable is that the master fully expects the servant to obey him, and of course does not thank the servant for doing what he was commanded to do. In the same way, we must learn to expect that the sick will be healed and demons will come out when we so command in the name of Jesus Christ. Since we have been given the authority, we are not all at surprised when miracles happen as we preach the gospel. We do not thank the infirmities and demons for leaving when we command them in Christ’s name. We expect them to obey as if they were our servants. This attitude is conducive for increasing our faith.
The secret to doing miracles to confirm the gospel is speaking with mountain-moving faith. This faith is based on the word of God. In addition to Luke 9:1-2 and Luke 10:1-2 where Jesus gave power and authority to His disciples, we may also cite Matthew and John’s renditions of the Great Commission:
Matthew 28:18 Then Jesus came to them and said, “All authority in heaven and on earth has been given to me. 19 Therefore go and make disciples of all nations, baptizing them in the name of the Father and of the Son and of the Holy Spirit, 20 and teaching them to obey everything I have commanded you. And surely I am with you always, to the very end of the age.”
John 20:21 Again Jesus said, “Peace be with you! As the Father has sent me, I am sending you.” 22 And with that he breathed on them and said, “Receive the Holy Spirit.
As the Father sent Jesus with full authority, Jesus has sent us with a limited measure of that authority. We are to go and exercise that authority for the preaching the gospel and making disciples. His authority resident in the power of the indwelling Holy Spirit will always be with us in this Commission. Clearly, Scripture tells us we have authority. Releasing the manifestation of that authority on earth requires speaking and commanding with mountain-moving faith.
Just as this faith is required in casting out demons, it is no less necessary in healing the sick in the context of preaching the gospel to the lost. The Gospels and Acts teach that the miracles took place when commands were issued by Jesus or the disciples in His name. Prayer, although essential, did not in itself bring about the healing. The reader is encouraged to read the accounts of miraculous healings recorded Gospels and Acts, and to follow the pattern which has been laid down for us. Jesus inserted His fingers into the ears of the deaf and placed His hands on the eyes of the blind, and commanded healing. Believers can do the same to confirm the gospel. I have witnessed such miracles many times on the mission field.
Can we minister to believers in the same way? In general, the answer is yes.