Pitṛgaṇa-Vibhāga (Classification of the Pitṛs) and the Śrāddha–Soma Nourishment Cycle
अपक्षस्येव गमनं गगने पक्षिणो यथा / वरिष्ठः सर्वधर्माणां मोक्षधर्मः सनातनः
apakṣasyeva gamanaṃ gagane pakṣiṇo yathā / variṣṭhaḥ sarvadharmāṇāṃ mokṣadharmaḥ sanātanaḥ
As a bird without wings cannot move through the sky, so among all dharmas the eternal dharma of moksha is the highest.