Because human anger does not produce the righteousness that God desires.

 James 1:1-27

If any of you lacks wisdom, you should ask God, who gives generously to all without finding fault, and it will be given to you. But when you ask, you must believe and not doubt, because the one who doubts is like a wave of the sea, blown and tossed by the wind.

Believers in humble circumstances ought to take pride in their high position. But the rich should take pride in their humiliation—since they will pass away like a wild flower.

Blessed is the one who perseveres under trial because, having stood the test, that person will receive the crown of life that the Lord has promised to those who love him.

But each person is tempted when they are dragged away by their own evil desire and enticed. Then, after desire has conceived, it gives birth to sin; and sin, when it is full-grown, gives birth to death.

Everyone should be quick to listen, slow to speak and slow to become angry, because human anger does not produce the righteousness that God desires. 

Do not merely listen to the word, and so deceive yourselves. Do what it says. 

Those who consider themselves religious and yet do not keep a tight rein on their tongues deceive themselves, and their religion is worthless. 

Why?

Wisdom, Humble, Tempted by evil desire, quick to listen, slow to speak, and slow to anger are our behaviors as Christians.

Keeping a tight rein on our own tongues is needed for everyone.

Don't just listen to a good speech or message, but do it as we listened.

How?

I have much work to do and listen, and practise it to be a good servant of the Lord.