The Importance Of Wisdom In All Things (Ecclesiastes 7:19-22).
‘Wisdom is a strength to the wise man more than ten rulers who are in a city.'
Ten is regularly used to mean ‘a number of'. It does not have a particular type of governance in mind, simply a collective leadership which is looked up to by the people. Thus the thought here may be that to a wise man his wisdom is better than the advice of a number of city rulers (who were supposed to represent joint wisdom), who would all, from the writer's experience, probably disagree anyway. The point is that wisdom is not necessarily with the majority, while a truly wise man's wisdom is solid, and reveals to him all sides of a question, enabling him to make wise decisions.
Or it may be instancing the fact that while it is good to have the backing of the city elders, it is even better to have wisdom, because true wisdom may well serve a man better than any number of supposedly wise city elders.
‘Surely there is not a righteous man on earth who does good and does not sin.'
But even a righteous man does not always advise rightly. For although the wise man may seek to be righteous, sadly he often fails (whether accidentally or purposely), as do all men. For there is no one who always does what is good. All are swayed by sin in one way or another. Thus all need more wisdom. (It was only later that One would come Who was the great exception and fully without sin - 1Pe 2:22; 2 Corinthians 5:21; Hebrews 4:15. But He was the exception that demonstrated the rule).
‘Also do not take to heart (‘give your heart to') all things that are spoken, in case you hear your servant curse you, for often also your own heart knows that you have in similar fashion cursed others.'
Another example of the need for wisdom is in respect of the hearing of rumours or listening to tell-tales. One thing the wise man will avoid doing is to take to heart careless words uttered by someone in an unguarded moment. This follows on the thought of Ecclesiastes 7:20. No one is totally righteous and therefore allowances must be made. When judging others we must ever remember our own faults, for we all make such mistakes. And there is a need for compassion. A man might hear his servant curse him, but if he takes this lesson to heart he will not lose a good servant as a result of a moment of folly. He will show mercy. Men even curse their best friends or their wives, thus we must expect from even a good servant an occasional curse behind our backs. It is again a question of not being over-righteous.