Matthew 6:6King James Version (KJV)
6 But thou, when thou prayest, enter into thy closet, and when thou hast shut thy door, pray to thy Father which is in secret; and thy Father which seeth in secret shall reward thee openly.
Mark 9:17-18King James Version (KJV)
17 And one of the multitude answered and said, Master, I have brought unto thee my son, which hath a dumb spirit;
18 And wheresoever he taketh him, he teareth him: and he foameth, and gnasheth with his teeth, and pineth away: and I spake to thy disciples that they should cast him out; and they could not.
Mark 9:25-29King James Version (KJV)
25 When Jesus saw that the people came running together, he rebuked the foul spirit, saying unto him, Thou dumb and deaf spirit, I charge thee, come out of him, and enter no more into him.
26 And the spirit cried, and rent him sore, and came out of him: and he was as one dead; insomuch that many said, He is dead.
27 But Jesus took him by the hand, and lifted him up; and he arose.
28 And when he was come into the house, his disciples asked him privately, Why could not we cast him out?
29 And he said unto them, This kind can come forth by nothing, but by prayer and fasting.