Charles Ellicott Commentary Proverbs 29:19

"A servant will not be corrected by words; For though he understand, he will not give heed." — Proverbs 29:19 (ASV)

A servant will not be corrected with words. — A slave must be corrected by sterner means; it is only fear of punishment which will move him; for though he understand, he will not answer, will not reply to your call, or render obedience to your command. The willing obedience of a son, and the grudging obedience of a slave, are contrasted in Romans 8:15.