King Indra said: Therefore with great frankness and without duplicity I shall now bow my head at the lotus feet of Bṛhaspati, the spiritual master of the demigods. Because he is in the mode of goodness, he is fully aware of all knowledge and is the best of the brāhmaṇas. Now I shall touch his lotus feet and offer my obeisances unto him to try to satisfy him.
Srimad Bhagavata Purana
श्रीमद्भागवतमहापुराणम्
मूल श्लोकः
अथाहममराचार्यमगाधधिषणं द्विजम् । प्रसादयिष्ये निशठः शीर्ष्णा तच्चरणं स्पृशन्
athāhamamarācāryamagādhadhiṣaṇaṃ dvijam | prasādayiṣye niśaṭhaḥ śīrṣṇā taccaraṇaṃ spṛśan
SB 6.7.15