You injure another man on account of ignorance. If you always bear in mind that you see God in every man and animal, and that God is sealed in the hearts of all living beings, you will not injure anybody.
You begin to injure others the moment you forget to see God in others.
Keep a spiritual diary. Note down in the diary when you become angry towards others, and when you hurt the feelings of others.
This is very, very important.
If you exhibit anger or hurt others, impose punishment on yourself. Give up meals at night. Do Japa, 50 Malas more.
If you proceed in this way for one or two years, you will doubtless achieve remarkable Shanti (peace), wonderful spiritual progress and strong will-power. Many kinds of miseries, troubles and mental worries will come to an end.
Devotion will develop. You will evolve rapidly.
Cited from "Kalyana-Kalpataru", 1935 issue
"Secrets of Bhakti-Yoga" article by Swami ShivAnanda