In Proverbs 10:21, the same contrast continues: righteous lips feed many, while fools die for lack of wisdom — amplifying the rod vs. wisdom theme.

Proverbs 10:31 contrasts the just mouth bringing wisdom with the perverse tongue cut out — mirrors the wise lips vs rod for the fool in the same chapter.

Proverbs 15:7 also contrasts the wise lips that disperse knowledge with the foolish heart that does not — echoing the same dichotomy.

Proverbs 17:10 echoes that a wise person responds to reproof while a fool needs many stripes, paralleling the rod for the fool vs wisdom for the understanding.

Proverbs 26:3 repeats the rod-for-the-fool imagery, directly reinforcing the punishment side of the contrast.

Proverbs 27:22 adds that even extreme punishment (pestle) cannot remove folly from a fool, deepening the rod's futility for the void of understanding.

Proverbs 7:7 describes a young man 'void of understanding' — the exact phrase from the second half, illustrating the type who receives the rod.

Proverbs 19:29 directly restates 'stripes for the back of fools' — an almost identical punishment for the same group as the rod for the void of understanding.

Proverbs 7:22 describes a fool heading to correction in stocks — similar punishment imagery to the rod for the fool.

Proverbs 15:23 highlights the joy of a timely word, complementing the value of wise speech — though without the rod contrast.

Proverbs 20:15 likens lips of knowledge to precious jewels, reinforcing the high value of wise speech — parallel to the first line.

Ecclesiastes 10:12 echoes the same contrast: wise speech is gracious, while a fool's lips bring self-destruction.

Psalm 32:9 compares those without understanding to animals needing bit and bridle — physical restraint parallels the rod for the void of understanding.

Isaiah 50:4 speaks of a tongue of the learned to sustain the weary — paralleling wise speech but in a prophetic context.

Luke 4:22 notes the gracious words of Jesus, exemplifying wise speech — a NT parallel to the value of understanding.