I have a vague memory of seeing something like this as a little boy. In the villages of Bengal there was a certain day in the last month of the year when people used to perform all kinds of ghastly but almost miraculous things. By their own mental powers they would make certain parts of their body insensitive. For example, they would put a hook under the spinal column and whirl on that hook. And after the hook was taken out, the wound would heal easily. You see, there was a period in India when people used to delight in practising hard asceticism; they would take a vow to live like great ascetics for a whole month and thereby they would generate these mental powers. Although in its extreme form asceticism has always been condemned, one cannot but admit that without it we become flabby, we have no vigour left within us. Therefore there should always be a touch of austerity in our existence. Physically, you all do that. You want to bathe in cold water; you want to go into snow; you know it is enervating to remain in heated rooms all the time. When we also treat the senses and the mind austerely, strength comes within them. Well, in the olden days in India people used to practise fasting, vigils, and so on. And as I said, on one day during the last month of the year they would demonstrate their powers. What I saw was probably the last vestige of these practices. I remember that two people held a long, sharp sword at its ends, and a man would stand barefoot on the edge of the blade and dance there without cutting his feet at all. Probably the explanation is that he maintained his balance very well, and that saved his feet from getting cut. Oftentimes when I have read this verse in the Upanishad I have remembered that childhood picture.
Yes, when we gain a certain balance in life, when the senses, the bodily forces, and the mind are balanced, then even in the midst of contrary circumstances we are able to proceed on; we do not get hurt. If we are unbalanced, we get hurt, we get cut. Probably that is what the author had in mind. Anyhow, it is enough for our purpose that he thought the spiritual path was very difficult to tread and that the utmost care should be taken in order to negotiate it successfully.
Where does this difficulty come from? And further, does everyone have to go through it? Here we can pinpoint certain facts about the spiritual path, and it will be helpful to recognize them, so that when anything untoward happens to us, we will be able to evaluate it rightly and not become unnecessarily discouraged.
To begin with, difficulties arise in spiritual life because we enter into it not properly prepared. You have all read, no doubt, many books on Vedanta or Yoga and you find the authors put things in a very nice, orderly fashion. They mention certain preliminary disciplines that are designed to bring our body, our senses, and our desires under our control, so that we attain to a state of purity and holiness. Although sensual, worldly desires may remain in a finer form, they do not arise to trouble us. The mind reaches a state of quietude and serenity in which we feel our closeness to God.
But the trouble about these rules is that even before we have fully acquired the virtues they speak of, our heart becomes eager to proceed along the path of the Spirit. We may not be fully disciplined; yet we would like to meditate. When you write systematically about a thing, it is very good to say: first practise this, then this and this, and then you will be ready for this step after step. In actual life, however, it does not work out so well. Not that truth is not there; these steps do follow one after another. The Yoga system of Patanjali, for example, speaks of astahga yoga, that is to say, there are eight parts, the last four of which are the steps of meditation: pratyahara, dharana, dhyana, and samadhi. Pratyahara means withdrawing the mind from things other than the Self or God. Then comes dharana, or holding your mind on the object of your meditation; you then learn to hold it there for a long time, and dharana becomes dhyana, or meditation, as we translate it in English. Not only is dhyana long and continuous, it has also to be profound: only in depth is continuity of meditation possible. So dhyana becomes very deep and uninterrupted, and when it has become so well established that, if you want, you can continue indefinitely, you then realize at an intense point what is called samadhi. Samadhi is, really speaking, meditation at its highest.