1 Thessalonians 3:5
For this cause, when I could no longer forbear, I sent to know your faith, lest by some means the tempter have tempted you…
There is a deep truth contained in the fabled story of old, where a mother, wishing to render her son invulnerable, plunged him into the Styx, but forgot to dip in his heel, by which she held him. We are baptized in the blood and fire of sorrow, that temptation may make us invulnerable; but let us remember that trials will assail our most vulnerable part, be it the head, or heart, or heel.
(F. W. Robertson, M. A.)
Parallel VersesKJV: For this cause, when I could no longer forbear, I sent to know your faith, lest by some means the tempter have tempted you, and our labour be in vain.