Those who really want to be Yogis must give up, once for all, this nibbling at things. Take up one idea. Make that one idea your life — think of it, dream of it, live on that idea. Let the brain, muscles, nerves, every part of your body, be full of that idea, and just leave every other idea alone. This is the way to success, and this is the way great spiritual giants are produced. Others are mere talking machines. If we really want to be blessed, and make others blessed, we must go deeper. The first step is not to disturb the mind, not to associate with persons whose ideas are disturbing. All of you know that certain persons, certain places, certain foods, repel you. Avoid them; and those who want to go to the highest, must avoid all company, good or bad. Practise hard; whether you live or die does not matter. You have to plunge in and work, without thinking of the result. If you are brave enough, in six months you will be a perfect Yogi.
– From Raja-Yoga & Patanjali Yoga-Sutra by Swami Vivekananda