Sri Adi Shankaracharya Bhagavatpada

दुर्लभं त्रयमेवैतद्देवानुग्रहहेतुकम् ।

मनुष्यत्वं मुमुक्षुत्वं महापुरुषसंश्रयः ॥

durlabhaṃ trayamevaitaddevānugrahahetukam |

manuṣyatvaṃ mumukṣutvaṃ mahāpuruṣasaṃśrayaḥ ||

Vivekachudamani, verse 3.

There are three things which are rare indeed and are due to the grace of God, namely a human birth, the longing for liberation, and the protecting care of a perfected sage.