Over and over again, the Upanishads exhort man to turn his attention to the realisation of his true nature by properly using his nature-given equipment of body, senses, and mind. They implore man not to convert his psycho-physical organism into a tomb of his soul, but to move forward, to evolve. This is the clear call of the Upanishads in one of their most memorable verses ( Katha . I.3.14), which Swami Vivekananda proclaimed from the housetops in East and West so forcefully in his oft-repeated clarion call: ‘‘Arise! Awake! And stop not till the goal is reached.’’

The fate of those who fail to heed this call is described in the third verse of the Isha Upanishad . Through spiritual blindness we enter into such forms and ways of life where we cannot get even the slightest inkling of this Atman, our true Self. There may be some people who do not mind being in darkness; but most people prefer to be in the light. Among those who so prefer, there are varying levels and stages of achievement. Utter worldliness is a rare occurrence; most people do get, in the language of Words­worth, ‘intimations of immortality’ at some time or other in their lives.

The experience may last hardly for a second, like a raindrop in a hot sandy waste. So does wisdom come and go; the clouds open for a while, and the sun shines. But once more the clouds close together again and the vision passes. So we go on from day to day. But by utilizing all life’s experiences, by spending a little time each day in thinking, evaluating our actions, and giving mo­mentum and direction to our lives, we shall be able to capture, for ever-lengthening periods, that fleeting vision that we have experi­enced; the ‘intimations of immortality’ become then a little more constant and steady.

The secret of spiritual progress is therefore to cultivate aware­ness of the Atman, our divine nature; to cultivate this constantly in and through all life’s experiences. It is this awareness that marks the difference between the worldly man and the spiritual seeker.

Reference: The Message of the Upanishads by Swami Ranganathananda (p.94)