Srimad-Bhagavatam: Canto 11 - Chapter 1 - Verse 45

Sanskrit:

सर्वा: समुद्धरेद् राजा पितेव व्यसनात् प्रजा: ।आत्मानमात्मना धीरो यथा गजपतिर्गजान् ॥ ४५ ॥

ITRANS:

sarvāḥ samuddhared rājāpiteva vyasanāt prajāḥātmānam ātmanā dhīroyathā gaja-patir gajān

Translation:

Just as the chief bull elephant protects all other elephants in his herd and defends himself as well, similarly, a fearless king, just like a father, must save all of the citizens from difficulty and also protect himself.

Purport:

Lord Kṛṣṇa, having concluded His discussion of brahminical duties, now describes the character and activities of a king. Protecting all of the citizens from difficulty is an essential duty for the king.