Matthew 19:26:

But Jesus beheld them, and said unto them, With men this is impossible; but with God all things are possible.

See also:

The Baseball Diamond of Healing
No Limits
How Long Does It Take to Build Faith for Healing That Works?
What if You’re the Minister and Someone Comes Forward with a Healing Request That You Know is Beyond Your Faith?
Objection: Jesus Could Not Have Borne All Birth Defects; His Body Would Have Lost Limbs and He Would Have Fallen off the Cross
Objection: Mental Illness Is Treatable but Not Curable