Proverbs 12:19 contrasts truthful lips (enduring) with lying tongues — reinforcing why lying is unfit for a prince.

Proverbs 16:10-13 says a king's lips should not sin and lying lips are an abomination — directly reinforcing the prince's standard in 17:7.

Proverbs 29:12 warns that a ruler who listens to lies corrupts his officials — showing the danger of lies in leadership, amplifying 17:7.

Psalm 101:3-5 details a ruler's resolve to avoid evil speech and slander — directly applying the prince's integrity from 17:7.

2 Samuel 23:3 describes a just ruler who fears God — the ideal for a prince, contrasting with lying lips in 17:7.

Psalm 50:16 rebukes the wicked who recite God's statutes — a parallel to a fool speaking excellently or a prince lying, both inappropriate speech.