Proverbs 25:15
"By long forbearing is a prince persuaded, and a soft tongue breaketh the bone."
Cross References (ranked by relevance)
Proverbs 15:1
A soft answer turneth away wrath: but grievous words stir up anger.
Ecclesiastes 10:4
If the spirit of the ruler rise up against thee, leave not thy place; for yielding pacifieth great offences.
Proverbs 16:14
The wrath of a king is as messengers of death: but a wise man will pacify it.
1 Samuel 25:14
But one of the young men told Abigail, Nabal’s wife, saying, Behold, David sent messengers out of the wilderness to salute our master; and he railed on them.