A rod of pride — that is, the pride shown in his speech is as a rod with which he strikes down others and himself.

In the mouth of the foolish (self-willed) is a rod of pride.— He suffers for his ill-judged say…

In the mouth of the foolish [is] a rod of pride
A proud tongue, or a tongue speaking proud and haughty things; with …

Pride grows from that root of bitterness which is in the heart. The root must be plucked up, or we cannot conquer this branch. The prudent words of…