Srimad Bhagavatam Canto 08, Chapter 05, Text 41

SB 8.5.41

vipro mukhad brahma ca yasya guhyam
 rajanya asid bhujayor balam ca
urvor vid ojo ’nghrir aveda-sudrau
 prasidatam nah sa maha-vibhutih
 
Translation by His Divine Grace A. C. Bhaktivedanta Swami Srila Prabhupada: 
 
The brahmanas and Vedic knowledge come from the mouth of the Supreme Personality of Godhead, the ksatriyas and bodily strength come from His arms, the vaisyas and their expert knowledge in productivity and wealth come from His thighs, and the sudras, 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 Bhagavatam Canto 08, Chapter 05, Text 39
Srimad Bhagavatam Canto 08, Chapter 05, Text 42