Proverbs 25:23
The north wind driveth away rain: so doth an angry countenance a backbiting tongue.
Cross-reference
Proverbs 26:20 links gossip to conflict — the same cause-and-effect as the backbiting tongue bringing angry looks.
Psalm 101:5 condemns slanderers — directly reinforcing the warning against a backbiting tongue in this proverb.
In 2 Corinthians 12:20, slander is listed alongside anger, echoing the backbiting tongue producing angry looks here.
In 1 Samuel 24:9, slanderers cause Saul's anger — a direct example of backbiting bringing angry looks as described here.
Ephesians 4:31 explicitly links slander and anger together, reinforcing the same cause-effect as the backbiting tongue and angry looks.
Psalm 15:3 describes the righteous as free from slander — the positive counterpart to the backbiting tongue warned against here.
Exodus 23:1 forbids spreading false reports — the same sin as the backbiting tongue here, though without the angry looks result.
Romans 1:30 lists slanderers among vices — a broader New Testament context for the sin of backbiting mentioned here.