Bhagwad Gita
Chapter 5, Verse 18
विद्याविनयसंपन्ने ब्राह्मणे गवि हस्तिनि।
शुनि चैव श्वपाके च पण्डिताः समदर्शिनः।।5.18।।
The humble sage, by virtue of true knowledge, sees with equal vision a learned and gentle brahmana, a cow, an elephant, a dog and a dog-eater [outcaste].