"Have a kind word for all — it spoils work to show temper. Let people say whatever they like, stick to your own convictions, and rest assured, the world will be at your feet. They say, “Have faith in this fellow or that fellow”, but I say, “Have faith in yourself first”, that’s the way. Have faith in yourself — all power is in you — be conscious and bring it out. Say, “I can do everything.” “Even the poison of a snake is powerless if you can firmly deny it.” Beware! No saying “nay”, no negative thoughts! Say, “Yea, Yea,” “So’ham, So’ham” — “I am He! I am He!”"
January 1, 1970
https://en.wikiquote.org/wiki/Swami_Vivekananda