James 5:15 NIV

1 John 5:14-16 NIV
This is the confidence we have in approaching God: that if we ask anything according to his will, he hears us. And if we know that he hears us—whatever we ask—we know that we have what we asked of him. If you see any brother or sister commit a sin that does not lead to death, you should pray and God will give them life. I refer to those whose sin does not lead to death. There is a sin that leads to death. I am not saying that you should pray about that.

James 1:6 NIV
But when you ask, you must believe and not doubt, because the one who doubts is like a wave of the sea, blown and tossed by the wind.

James 5:13 NIV
Is anyone among you in trouble? Let them pray. Is anyone happy? Let them sing songs of praise.

James 5:16 NIV
Therefore confess your sins to each other and pray for each other so that you may be healed. The prayer of a righteous person is powerful and effective.

Mark 16:17-18 NIV
And these signs will accompany those who believe: In my name they will drive out demons; they will speak in new tongues; they will pick up snakes with their hands; and when they drink deadly poison, it will not hurt them at all; they will place their hands on sick people, and they will get well.”

Matthew 17:20 NIV
He replied, “Because you have so little faith. Truly I tell you, if you have faith as small as a mustard seed, you can say to this mountain, ‘Move from here to there,’ and it will move. Nothing will be impossible for you.”

Matthew 21:21-22 NIV
Jesus replied, “Truly I tell you, if you have faith and do not doubt, not only can you do what was done to the fig tree, but also you can say to this mountain, ‘Go, throw yourself into the sea,’ and it will be done. If you believe, you will receive whatever you ask for in prayer.”