Sri Aurobindo translates Mundaka Upanishad, Chapter 3, Section 2, Verse 4: “This Self cannot be won by any who is without strength, nor with error in the seeking, nor by an askesis without the true mark: but when a man of knowledge strives by these means his Self enters into Brahman, his abiding place.”
People frequently treat the religious or spiritual life as a form of escape from the pressures or disappointments of life in the world; in other words, it is seen as a form of weakness, an inability to grapple with life that leads an individual to withdraw and find comfort in the forest, the cave, the monastery, the cloister. The Upanishad here makes it clear that a seeking based on vital weakness or an error in knowledge or a false premise for the concentration that is required does not achieve the realisation. The spiritual life is not for the weak or those who exercise a limited and deluded understanding.
History has shown us examples of such error when monks undertake violent self-flagellation as their penance, or when they otherwise abuse the Self within them with undue mortification which they believe somehow proves their dedication. The vital nature in these individuals exhibits weakness. Such seekers believe that suffering of the physical body and vital nature is the path to achievement.
If we go back to the criteria set by this Upanishad earlier, we see that the basis is a poise of serene joyful receptivity, a quiet mind and a focused concentration. Such a status does not arise from weakness or misdirected energy. When the seeker finds that right poise, however, the door opens for the Self to “enter into Brahman” and abide there.
Sri Aurobindo, The Upanishads, Mundaka Upanishad, pp. 193-210