Acts 3:16 NKJV

And His name, through faith in His name, has made this man strong, whom you see and know. Yes, the faith which comes through Him has given him this perfect soundness in the presence of you all.

Mark 11:22 NKJV

So Jesus answered and said to them, “Have faith in God. Have faith in God.

Hebrews 11:6 NKJV

But without faith it is impossible to please Him, for he who comes to God must believe that He is, and that He is a rewarder of those who diligently seek Him.

Mark 9:14–24 NKJV

And when He came to the disciples, He saw a great multitude around them, and scribes disputing with them. 15 Immediately, when they saw Him, all the people were greatly amazed, and running to Him, greeted Him. 16 And He asked the scribes, “What are you discussing with them?” 17 Then one of the crowd answered and said, “Teacher, I brought You my son, who has a mute spirit. 18 And wherever it seizes him, it throws him down; he foams at the mouth, gnashes his teeth, and becomes rigid. So I spoke to Your disciples, that they should cast it out, but they could not.”

9 He answered him and said, “O faithless generation, how long shall I be with you? How long shall I bear with you? Bring him to Me.” 20 Then they brought him to Him. And when he saw Him, immediately the spirit convulsed him, and he fell on the ground and wallowed, foaming at the mouth.21 So He asked his father, “How long has this been happening to him?”And he said, “From childhood. 22 And often he has thrown him both into the fire and into the water to destroy him. But if You can do anything, have compassion on us and help us.”23 Jesus said to him, “If you can believe, all things are possible to him who believes.”24 Immediately the father of the child cried out and said with tears, “Lord, I believe; help my unbelief!”

Mark 11:23 NKJV

For assuredly, I say to you, whoever says to this mountain, ‘Be removed and be cast into the sea,’ and does not doubt in his heart, but believes that those things he says will be done, he will have whatever he says

To Believe

2 Corinthians 4:13 NKJV

And since we have the same spirit of faith, according to what is written, “I believed and therefore I spoke,” we also believe and therefore speak

Believe Greek – pisteuō

to think to be true, to be persuaded of, to credit, place confidence in
of the thing believed
to credit, have confidence

Doubt Not

Mark 11:23 NKJV

For assuredly, I say to you, whoever says to this mountain, ‘Be removed and be cast into the sea,’ and does not doubt in his heart, but believes that those things he says will be done, he will have whatever he says

Hebrews 10:23 NKJV

Let us hold fast the confession of our hope without wavering, for He who promised is faithful.

2 Corinthians 10:4–6 NKJV

For the weapons of our warfare are not carnal but mighty in God for pulling down strongholds, 5 casting down arguments and every high thing that exalts itself against the knowledge of God, bringing every thought into captivity to the obedience of Christ, 6 and being ready to punish all disobedience when your obedience is fulfilled.

“You have to meditate upon the Word Of God until all doubts are driven out!” -Kenneth Hagin

Matthew 17:19–21 NKJV

Then the disciples came to Jesus privately and said, “Why could we not cast it out?”
20 So Jesus said to them, “Because of your unbelief; for assuredly, I say to you, if you have faith as a mustard seed, you will say to this mountain, ‘Move from here to there,’ and it will move; and nothing will be impossible for you. 21 However, this kind does not go out except by prayer and fasting.”

Mark 19:20 NKJV

20 Then they brought him to Him. And when he saw Him, immediately the spirit convulsed him, and he fell on the ground and wallowed, foaming at the mouth.

Matthew 10:1NKJV

And when He had called His twelve disciples to Him, He gave them power over unclean spirits, to cast them out, and to heal all kinds of sickness and all kinds of disease.