Verse that says that he who cannot govern himself cannot govern others? Where in Holy Scriptures does it say that he who cannot govern himself cannot govern others?
Where in Holy Scriptures does it say that he who cannot govern himself cannot govern others?

As @curiousdannii &amp; @NigelJ pointed out, 1 Tim 3:5 is probably the closest NT single-verse match (Douay-Rheims translation):

But if a man know not how to rule his own house, how shall he take care of the church of God?

Since you are looking for OT Wisdom literature, another (but less exact) match can be the combination of these 2 Proverbs verses (Pr 25:28 and Pr 16:32), comparing the rule of one's self with the rule of a city (by a king), showing both the defensive and offensive attributes of self-government respectively (ESV translation):
Pr 25:28:

A man without self-control is like a city broken into and left without walls.

Pr 16:32:

Whoever is slow to anger is better than the mighty, and he who rules his spirit than he who takes a city.

Source: bibletools.org topical study on Self Government