James 1:19–20
"Wherefore, my beloved brethren, let every man be swift to hear, slow to speak, slow to wrath: For the wrath of man worketh not the righteousness of God."
James gives a three-part rhythm — listen fast, speak slowly, anger slowly — and then the reason: human wrath is simply not the tool that accomplishes God's purposes. No matter how justified the anger feels, it rarely produces the outcomes righteousness requires. This is one of the most practically useful verses on self-control in the entire New Testament.