Mundaka-3-2-2-kāmān yaḥ

Sri Shankara’s Commentary (Bhashya) translated by S. Sitarama Sastri

Com.—This text shows that the primary help to him who is desirous of emancipation is the renunciation of all desire. He who covets visible or invisible objects of desire, brooding on their virtues is born again and again with those desires of external objects which are incentive to the performance of good and bad deeds. Wherever his desires direct him to perform karma for the realisation of their objects, he is born with those self-same desires in those objects. But of him who from a sound knowledge of the absolute truth has all his desires fulfilled, because the Atman is the object of his desire and whose Atman through knowledge has been made to assume its highest, i.e., true form by the removal of the lower form imposed on it by ignorance, all desires impelling him to do meritorious and sinful deeds are destroyed even while his body lasts. The drift is that desires do not spring up, because the causes of their rising are destroyed.

Links
Various resources on the Mundakopanishad
Upanishad Series – Mundakopanishad Commentary by Swami Chinmayananda