New Revised Standard Version
He said to them, “This kind can come out only through prayer.”

Contemporary English Version
Jesus answered, "Only prayer can force out this kind of demon."

New American Bible
He said to them, “This kind can only come out through prayer.”

Douay-Rheims Bible
And he said to them: This kind can go out by nothing, but by prayer and fasting.

And he said to them: This kind can go out by nothing, but by prayer and fasting.

This.

Matthew 12:45 Then he goeth, and taketh with him seven other spirits more wicked than himself, and they enter in and dwell there: and the last state of that man is made worse than the first. So shall it be also to this wicked generation.

Luke 11:26 Then he goeth and taketh with him seven other spirits more wicked than himself: and entering in they dwell there. And the last state of that man becomes worse than the first.

by prayer.

1 Kings 17:20-22 And he cried to the Lord, and said: O Lord, my God, hast thou afflicted also the widow, with whom I am after a sort maintained, so as to kill her son? . . .

2 Kings 4:33,34 And going in, he shut the door upon him, and upon the child, and prayed to the Lord. . . .

Matthew 17:21 And when they abode together in Galilee, Jesus said to them: The Son of man shall be betrayed into the hands of men:

Acts 9:40,41 And they all being put forth, Peter, kneeling down, prayed. And turning to the body, he said: Tabitha, arise. And she opened her eyes and, seeing Peter, sat up. . . .

2 Corinthians 12:8 For which thing, thrice I besought the Lord that it might depart from me.

Ephesians 6:18 By all prayer and supplication praying at all times in the spirit: and in the same watching with all instance and supplication for all the saints:

James 5:15 And the prayer of faith shall save the sick man. And the Lord shall raise him up: and if he be in sins, they shall be forgiven him.

fasting.

Daniel 9:3 And I set my face to the Lord, my God, to pray and make supplication with fasting, and sackcloth, and ashes.

Acts 14:23 And when they had ordained to them priests in every church and had prayed with fasting, they commended them to the Lord, in whom they believed.

1 Corinthians 9:27 But I chastise my body and bring it into subjection: lest perhaps, when I have preached to others, I myself should become a castaway.

2 Corinthians 6:5 In stripes, in prisons, in seditions, in labours, in watchings, in fastings,

2 Corinthians 11:27 In labour and painfulness, in much watchings, in hunger and thirst, in fastings often, in cold and nakedness: