Galatians 6:17:

From henceforth let no man trouble me: for I bear in my body the marks of the Lord Jesus.

See also:

Objection: We Know That God Did Not Heal Paul, Because He Said That He Bore Marks in His Body (Galatians 6:17)
Objection: Paul First Preached at Galatia Due to a Physical Infirmity
Notes on Galatians 4:13