The brāhmaṇas and Vedic knowledge come from the mouth of the Supreme Personality of Godhead, the kṣatriyas and bodily strength come from His arms, the vaiśyas and their expert knowledge in productivity and wealth come from His thighs, and the śūdras, who are outside of Vedic knowledge, come from His feet. May that Supreme Personality of Godhead, who is full in prowess, be pleased with us.
Srimad Bhagavata Purana
श्रीमद्भागवतमहापुराणम्
मूल श्लोकः
विप्रो मुखं ब्रह्म च यस्य गुह्यं राजन्य आसीद्भुजयोर्बलं च । ऊर्वोर्विडोऽजोऽङ्घ्रिरवेदशूद्रौ प्रसीदतां नः स महाविभूतिः
vipro mukhaṃ brahma ca yasya guhyaṃ rājanya āsīdbhujayorbalaṃ ca | ūrvorviḍo'jo'ṅghriravedaśūdrau prasīdatāṃ naḥ sa mahāvibhūtiḥ
SB 8.5.41