The Compendium of Caraka 1.9.27

1.9.27

tatra ślokau
bhiṣagjitaṃ catuṣpādaṃ pādaḥ pādaścaturguṇāḥ /
bhiṣak pradhānaṃ pādebhyo yasmādvaidyastu yadguṇaḥ //

Here are the two verses:
Medicine has four pillars, and each pillar has four qualities; / the physician is the foremost among the pillars, because of whom and with what qualities the physician acts.