People have the habit of dealing lightly with thoughts that come. And the atmosphere is full of thoughts of all kinds which do not in fact belong to anybody in particular, which move perpetually from one person to another, very freely, much too freely, because there are very few people who can keep their thoughts under control.
When you take up the Buddhist discipline to learn how to control your thoughts, you make very interesting discoveries. You try to observe your thoughts. Instead of letting them pass freely, sometimes even letting them enter your head and establish themselves in a quite inopportune way, you look at them, observe them and you realise with stupefaction that in the space of a few seconds there passes through the head a series of absolutely improbable thoughts that are altogether harmful.
You believe you are so good, so kind, so well disposed and always full of good feelings. You wish no harm to anybody, you wish only good – all that you tell yourself complacently. But if you look at yourself sincerely as you are thinking, you notice that you have in your head a collection of thoughts which are sometimes frightful and of which you were not at all aware.
For example, your reactions when something has not pleased you: how eager you are to send your friends, relatives, acquaintances, everyone, to the devil! How you wish them all kinds of unpleasant things, without even being aware of it! And how you say, “Ah, that will teach him to be like that!” And when you criticise, you say, “He must be made aware of his faults.” And when someone has not acted according to your ideas, you say, “He will be punished for it!” and so on.
You do not know it because you do not look at yourself in the act of thinking. Sometimes you know it, when it becomes a little too strong. But when the thing simply passes through, you hardly notice it – it comes, it enters, it leaves. Then you find out that if you truly want to be pure and wholly on the side of the Truth, then that requires a vigilance, a sincerity, a self-observation, a self-control which are not common. You begin to realise that it is difficult to be truly sincere.
You flatter yourself that you have nothing but good feelings and good intentions and that whatever you do, you do for the sake of what is good – yes, so long as you are conscious and have control, but the moment you are not very attentive, all kinds of things happen within you of which you are not at all conscious and which are not very pretty.
If you want to clean your house thoroughly, you must be vigilant for a long time, for a very long time and especially not believe that you have reached the goal, like that, at one stroke, because one day you happened to decide that you would be on the right side. That is of course a very essential and important point, but it must be followed by a good many other days when you have to keep a strict guard on yourself so as not to belie your resolution.
4 April 1958