At the doorway of that psychological treasure-house which we know as the aphorisms of Patanjali, is written the injunction, "Thou shalt hinder the modifications of the Thinking Principle." The thinking principle is the mind, and its modifications are the changes which the mind undergoes as it constantly assumes the form of the thing thought of. This opening injunction means, then, that the mind must be controlled as a preliminary step toward the science at which all his teachings are veiled and usually misunderstood hints.
If we are in any doubt as to the way in which we are to apply this precept to ourselves, let us try to examine into, and to trace the workings of our minds during any period of five minutes when we are not actively mentally employed. That is to say, let us arrest our thoughts at any given moment and ask where that thought originated and what preceded it. We shall probably find that another and quite different thought preceded it and suggested it, that it is often difficult to detect the suggestive thread of connection, and we shall also find that within the space of a very few seconds a very great number and a very great variety of so-called "thoughts" have modified our minds. Then we awake to the disturbing realization that during a considerable portion of the day our minds are like engines without drivers, or of which the drivers are sleeping in the baggage car. Hence the injunction to hinder these modifications.
Another idea immediately presents itself. We have seen that the mind assumes the form of the thing thought of. That means that the mind is continually assuming forms induced by thoughts which we have not invited, thoughts which are frequently too utterly trivial to be worthy of the dignity of mind-modifiers, and all too often thoughts which, if challenged would be unable to give the passwords of purity or of fraternity. The question grows more serious still when we remember that a modification once induced, predisposes to its own reproduction as a stick once bent is the more readily bent thereafter. First comes a possibility, then a tendency, and then a habit, and at last the mind becomes so habituated to a particular form of modification, it may be a selfish or a vicious modification, that it resents and resists any effort to change the shape which years of selfish or vicious thoughts have given it.
To "hinder the modifications" does not mean that we are not to think, but that we are to be masters of our thoughts, so completely master and guardian that during neither day nor night shall any thought pass the most sacred doorway of the mind unless it first stand and deliver the credentials of purity, which are the only passwords to that holy place.
But now an even greater idea comes, bringing with it a vision of infinite possibilities which await us. If the mind is modified by the thing thought of, if that modification establishes a tendency and then a habit, we can equally shape the mind upon some great ideal, and we can hold it in that shape until this newly established and beautiful tendency overcomes and transmutes all previous tendencies, and the mind habitually assumes a beautiful form, resisting and resenting all attempts to mould it into the base or the impure, and when we have done that we have done more than we now know of, because we have made ourselves in very truth the Temple of God, and out of the Temple shall stream the strong divine light which is the light which lighteth every man that cometh into the world and is the whole world's light.
But to do this we must try, and in every day there are twenty-four hours in which we can try without ceasing. For this needs no time set apart, nor special opportunity. This is the work which we can carry with us into every detail of daily life, and which will guard and glorify our sleep.