Every religion has its rituals. We have plenty of them in Hinduism. Sandhyā or sandhyākarma or sandhyāvandana is a fundamental Vedic ritual obligatory on all the dvijas (the ‘twice born,’ viz., the brāhmaṇas, the kṣattriyas and the vaiśyas). It is essentially an upāsanā (meditation, spiritual practice) and has several steps designed to elevate the mind to levels of meditation and mysticism. Aghamarṣaṇa is one such step in the process. It consists of taking a few drops of water in the right hand shaped like the gokarṇa (the ear of a cow), holding it near the nose and breathing out from the nose on the water (with the idea of driving away sin from oneself) to the accompaniment of the three Ṛgvedic verses beginning with ‘ṛtaṁ ca’ (vide Ṛgveda Saṁhitā 10.190. 1-3), and throwing away the water to one’s left on the ground. Though the subject matter of these mantras is creation and the Creator, the mantras themselves are reputed to be ‘aghamarṣana’ or sin-effacing. These mantras can also be repeated during bath and as an expiation of sins.
The mantras beginning with ‘hiraṇya-śṛṅgaṁ varuṇaṁ prapadye’ and ending with ‘ākrāntsamudraḥ’ which form part of the Mahānārāyaṇa Upaniṣad (55-70) are known as Aghamarṣaṇasūkta. The three ṛks of the aghamarṣaṇa ritual (‘ṛtaṁ ca’) are also included in this. This Aghamarṣaṇasūkta is normally recited while taking bath in ponds or rivers. It is accredited with the power of destroying all sins, whether ordinary ones like the one incurred by eating the food given by evil ones or heinous ones like committing adultery and murder of the embryo.