In the march towards Truth, anger, selfishness, hatred, etc., naturally give way, for otherwise Truth would be impossible to attain. A man who is swayed by passions may have good enough intentions, may be truthful in word, but he will never find the Truth.
To seek to extinguish anger utterly is but a bravery of the Stoics. We have better oracles: 'Be angry, but sin not.' 'Let not the sun go down upon your wrath.'
Evil company is always to be shunned; because it leads to lust and anger, illusion, forgetfulness of the goal, destruction of the will (lack of perseverance), and destruction of everything. (Narada Bhakti Sutra)
I know, to banish anger altogether from one's breast is a difficult task. It cannot be achieved through pure personal effort. It can be done only by God's grace.
He who begins by loving Christianity more than Truth, will proceed by loving his sect or church better than Christianity, and end in loving himself better than all.
So a voice in the mountain is enough to let loose an avalanche. A word too much may be followed by a caving in. If the word had not been spoken, it would not have happened.