Hebrews 12:12-13:

Wherefore lift up the hands which hang down, and the feeble knees;
And make straight paths for your feet, lest that which is lame be turned out of the way; but let it rather be healed.

Notes on Hebrews 12:12-13:

This quotes Isaiah 35:3.  Both here and in Isaiah, the cause of the hands hanging down and feeble knees is fear.  The point is definitely not that God makes you physically ill to chastise you!  (Many have interpreted this verse that way to their detriment.  See the reply to the objection below.)  The idea is not to fear God (in an anxious, as opposed to reverent, way) just because He corrects you.

In all other places where the Greek word translated feeble (paralyo) appears in the Bible, it refers to paralysis!  Do you honestly believe that God strikes people with paralysis of the knees to teach them something?  I don’t.  Would you do that to your children to correct them?

If someone is sick because of fear, this verse would apply to his healing, but in its context, this is not a good verse to use as a healing proof-text for lame people.

See also:

Objection: Sickness Can Be the Chastening of the Lord
Condition: Lameness
Condition: Weakness