He that being often reproved hardeneth his neck; literally, a man of reproofs—one who has had a long experience of rebukes and warnings. Compare "a man of sorrows" (Isaiah 53:3). The hardening of the neck is a metaphor derived from obstinate draught animals who will not submit to the yoke (Deuteronomy 10:16; Jeremiah 2:20; Jeremiah 27:8).
Christ calls his yoke easy, and bids his followers to bear it bravely (Matthew 11:29. etc.). The reproofs may arise from the Holy Spirit and the conscience, from the teaching of the past, or from the counsel of friends.
The LXX. (as some other Jewish interpreters) takes the expression in the text actively, "A man who reproves ( ἐλέγχων) is better than one of stiff neck." Shall suddenly be destroyed, and that without remedy (Proverbs 6:15; Proverbs 15:10).
The incorrigible and self-deluding sinners shall come to a fearful and sudden end, though retribution be delayed (comp. Job 34:20; Psalms 2:9; Jeremiah 19:11). And there is no hope in their end; despising all correction, they can have no possibility of restoration.
We may refer, as an illustration, to that terrible passage in the Epistle to the Hebrews (Hebrews 6:4, etc.), and to the fate of the Jews unto the present day. Septuagint, "For when he is burning suddenly, there is no remedy."