John Gill Commentary Proverbs 17:21

"He that begetteth a fool [doeth it] to his sorrow; And the father of a fool hath no joy." — Proverbs 17:21 (ASV)

He that begets a fool [does it] to his sorrow
As it proves in the issue; though it was joy to him when a man child was born, and took delight in him while in infancy and childhood, and promised himself much happiness in him when at years of discretion; but, instead of that, he departs from his education principles, despises all parental counsels and advice, and goes into all the extravagance of sin and folly; which is an heartbreaking to his godly and religious parents; for this is to be understood; not of an idiot, but of a wicked son, taking bad courses;

and the father of a fool has no joy ;
in his son, but sorrow, and has scarce any joy or pleasure in anything else in all his enjoyments; the trouble he is filled with on his account embitters all he has, that he can take no satisfaction, or have any comfort of life; the concern for his son is uppermost in his thoughts, and hinders him from taking that pleasure which otherwise he might enjoy.