Charles Ellicott Commentary Judges 16:19

"And she made him sleep upon her knees; and she called for a man, and shaved off the seven locks of his head; and she began to afflict him, and his strength went from him." — Judges 16:19 (ASV)

Made him sleep upon her knees. — As his locks could hardly be shaved off without awakening him from any ordinary sleep, the expression looks as if she had administered some “drowsy syrup,” like mandragora.

She called for a man. —Probably the concealed spy (Judges 16:9). “Laying down his head among the strumpet flatteries ... while he sleeps and thinks no harm, they, wickedly shaving off all those bright and weighty tresses ... which were his ornament and his strength, deliver him over ...” (Milton, Reason of Church Government).

Whether the pagan legends of the lock of Nisus or Pterolaus were distant echoes of this incident we cannot say.

But the hair of Samson was no magical amulet; it was only a sign of dedication to God. While he kept his vow, the strength remained; it only departed when the vow was shamefully broken.

She began to afflict him.—Rather, to humble him (Judges 19:24). We cannot tell the exact meaning of the clause, since it is only in the next verse that Samson is said to awaken. (Compare to Proverbs 7:26.)