The Mundaka Upanishad first describes for Saunaka the elements of the lower knowledge and then contrasts this with the higher knowledge. The lower knowledge represents the means of action and success in the outer world. One can attain all one’s desires and achieve states of heavenly enjoyment through proper understanding of the Vedas and related sciences. Yet all of these results are transitory and to some degree illusory as they come, and then they go. The higher knowledge is permanent and is the knowledge of the Supreme, the Absolute, the Unchanging.
Verse 5 of Chapter 1, Section 1 of the Mundaka Upanishad: “Of which the lower, the Rig-Veda and the Yajur-Veda, and the Sama-veda and the Atharva-veda, chanting, ritual, grammar, etymological interpretations, and prosody and astronomy. And then the higher by which is known the Immutable.”
The Vedic knowledge and the various other sciences are essential for worldly action, and to some degree, the concentration or focus involved develops the faculties and prepares them for the next step of human development. The seeking after the higher knowledge of the Immutable requires deep concentration and the tools developed in what is known as Jnana Yoga are based initially on powers developed through the concentration on the Vedic texts and their application in action, including chanting, rituals, and various sacrificial forms which are not to be taken solely in the restricted sense of religious rituals, but in the sense of the dedication of one’s time, energy, and focus on spiritual truths of existence, and the implementation of these principles in outer action of all kinds. It is true that in certain phases of development, Vedantic practitioners and scholars have limited the scope to observance of religious rituals, but apparently the intended scope was wider and encompassed all of the life activities. This is one significance of the teaching being given to a “house lord” in this Upanishad, to remind the seekers that this knowledge is not restricted solely to those who have dedicated themselves to a religious life of abstention and one-pointed exclusive concentration.
Sri Aurobindo, The Upanishads, Mundaka Upanishad, pp. 193-210