There was another, on the control of the thoughts, from the text, "Leading into captivity every thought." This made a deep impression on the students.

I seem to hear the tones of his voice now.
The Doctor described with a terrific effect the thinking over in imagination scenes of vice by the youth who seemed to the world outside to fall suddenly from virtue.

He said there was no such thing as a sudden fall from virtue.

The scene had been enacted in thought and the man had become rotten before the time of the outward act.
"Sometimes the novice in crime thinks himself ready to act when he is not; as appears from his hesitancy and reluctance when the moment for action arrives.

If, however, this unexpected recoil of his nature does not induce him to change his purpose altogether, he knows but too well how to supply the defect in training for sin.