Ecclesiastes 10:3

Yea, even by the way, as the foolish man walketh along, his sense faileth him - and he telleth everyone that, foolish, is he!

Proverbs 13:16

Every prudent man, maketh use of knowledge, but, a dullard, spreadeth folly.

Proverbs 18:2

A dullard, delighteth not, in understanding, in nothing save the exposing of his own heart.

Proverbs 18:6

the lips of a dullard, enter into contention, and his mouth, for blows, crieth out.

Ecclesiastes 5:3

For a dream cometh through the multitude of business, - and, the voice of a dullard, is with a multitude of words.

1 Peter 4:4

Wherein they are taken by surprise that ye run not with them into the same overflow of riotous excess, - uttering defamation:

Treasury of Scripture Knowledge

Summary

Yea also, when he that is a fool walketh by the way, his wisdom faileth him, and he saith to every one that he is a fool.

Bible References

And he

Ecclesiastes 5:3
For a dream cometh through the multitude of business, - and, the voice of a dullard, is with a multitude of words.
Proverbs 13:16
Every prudent man, maketh use of knowledge, but, a dullard, spreadeth folly.
Proverbs 18:2
A dullard, delighteth not, in understanding, in nothing save the exposing of his own heart.
1 Peter 4:4
Wherein they are taken by surprise that ye run not with them into the same overflow of riotous excess, - uttering defamation:

General references

1 Kings 12:8
But he declined the counsel of the elders which they gave him, and consulted with the young men, who had grown up with him, who were standing before himself;
Proverbs 14:33
In the heart of the intelligent, reposeth wisdom, but, in the midst of dullards, it maketh itself known.
Proverbs 17:28
Even a fool, holding his peace, is accounted, wise, - He that closeth his lips, is thought to have understanding.