Human birth is rare

In the next mantra, yamarāja describes how the world behaves out of fear of brahman?

bhayādasyāgnistapati bhayāttapati sūryaḥ |

bhayādindraśca vāyuśca mṛtyurdhāvati pañcamaḥ ||2.3.3||

Fire burns out of fear of this (brahman). The sun heats up out of fear. Indra and vāyu

function out of fear, and yama, the fifth, runs (out of fear).

All devatā that govern the natural forces function perfectly because of the fear of brahman (Īśvara): agnistapati - fire burns; tapati sūryaḥ - sun shines; indraśca - Indra brings rain; and vāyuśca - wind blows. All these functions bhayād - because out of fear, following the law that is itself a manifestation of brahman. None of these are accidental. When things function in a certain manner, there must be a sentient principle behind their functioning. Brahman, the invisible intelligence, maintains these in the form of cosmic order. Yamarāja himself says mṛtyurdhāvati pañcamaḥ - he, the fifth devatā (in the list of this mantra), also runs (performing his duty) out of fear of brahman, means every being’s lifespan is in the order. Everyone fears yamarāja (death), who himself fears brahman. Therefore, to gain protection from yamarāja, one should take refuge in brahman. The only way to escape mortality is through Īśvara-aikyam (knowing oneness between īśvara, the universe and the self), which is symbolized by the story of mārkaṇdeya, who embraced śivaliṅga when chased by yamarāja. It is not a physical embrace; rather, it is in the form of aham brahma asmi, knowing oneself as the immortal cause of the entire universe.

The next mantra discusses the prerequisite for brahmajñānam.

iha cedaśakad boddhuṃ prāk śarīrasya visrasaḥ |

tataḥ sargeṣu lokeṣu śarīratvāya kalpate ||2.3.4||

If one is able to know (brahman) here before the fall of the body, (then one is liberated). Otherwise, one becomes fit for taking another body in the world of creatures.

The first three mantra discussed the nature of brahman. This mantra discusses the requirement for brahmajñāna, which is human birth. Obtaining a human birth is rare. We must understand the importance of human birth and utilize it properly. To cross this ocean of saṁsāra, we need a special boat in the form of human body. The cost of this valuable boat is puṇya. This boat is not permanent and therefore, we should cross before it is lost. iha cedaśakad boddhuṃ prāk śarīrasya visrasaḥ - if a person knows this truth in this human birth, he will be released from the life of becoming before he dies. In other words, he will be a jīvanmukta (free while living). tataḥ sargeṣu lokeṣu śarīratvāya kalpate - if he misses this opportunity in this life, he becomes fit only to take another birth; remaining in the cycle of samsāra.