Matthew 17:20
Then said Jesus unto them, Because of your unbelief: for verily I say unto you, If ye have faith as a grain of mustard, ye shall say to this mountain, Remove from hence, thither, and it will remove; and nothing will be impossible for you.
Luke 17:6
And the Lord said, If ye had faith as a grain of mustard, ye might say to that sycamore-tree, Be rooted up, and be planted in the sea; and it would obey you.
Matthew 13:31
Another parable he proposed to them, saying, The kingdom of heaven is like a grain of mustard, which a man took and sowed in his field:
Matthew 21:21
But Jesus addressing them, said, Verily I tell you, if ye have faith, and entertain no doubt, not only shall ye do what is done to the fig-tree, but if ye should even say to this mountain, Be lifted up, and be cast into the sea, it be done.
Mark 11:23
For verily I say to you, That whosoever shall say to this mountain, Be thou lifted up, and be thou cast into the sea; and shall harbour no doubt in his heart, but believe that what he saith shall come to pass; whatsoever he may speak shall be done for him.
1 Corinthians 13:2
And though I have the gift of prophecy, and know all mysteries, and all manner of science; and though I have all faith, so that I could remove mountains, but have not love, I am nothing.
Mark 9:23
Then said Jesus unto him, This [is the point]: if thou canst believe, all things are possible to him that believeth.
Matthew 14:30-31
But seeing the wind boisterous, he was afraid; and beginning to sink in the deep, he cried out, saying, Lord save me.
Matthew 17:9
And when they were coming down from the mountain, Jesus commanded them, saying, Tell no man the vision, until the Son of man is risen from the dead.
Matthew 17:17
Then Jesus answering, said, O generation, faithless, and perverse! how long shall I be with you? how long shall I bear with you? bring him hither to me.
Mark 4:31
It is like a grain of mustard, which when it is sown in the earth, is among the least of all the seeds which are upon the earth:
Luke 1:37
For there is nothing impossible with God.
Luke 18:27
And he said, The things impossible with men, are possible with God.
John 11:40
Jesus saith unto her, Did I not tell thee, that, if thou wouldest believe, thou shalt see the glory of God?
1 Corinthians 12:9
to another faith by the same Spirit; to another the gifts of healing [diseases] by the same Spirit;
Hebrews 3:19
So we see that they could not enter in because of unbelief.