SB 11.22.42

indriyāyana-sṛṣṭyedaṁ
 trai-vidhyaṁ bhāti vastuni
bahir-antar-bhidā-hetur
 jano ’saj-jana-kṛd yathā
Word for word: 
indriya-ayana — by the resting place of the senses (the mind); sṛṣṭyā — because of the creation (of identification with a new body); idam — this; trai-vidhyam — threefold variety (of high, middle and low class); bhāti — appears; vastuni — in the reality (the soul); bahiḥ — external; antaḥ — and internal; bhidā — of the differences; hetuḥ — the cause; janaḥ — a person; asat-jana — of a bad person; kṛt — the progenitor; yathā — as.
Translation: 
Because the mind, which is the resting place of the senses, has created the identification with a new body, the threefold material variety of high, middle and low class appears as if present within the reality of the soul. Thus the self creates external and internal duality, just as a man might give birth to a bad son.
Purport: 

The wealth, beauty, strength, intelligence, fame and detachment of different bodies are considered to be excellent, normal or inferior according to the material situation. The spirit soul acquires a particular body and thus judges himself and others to be high, middle or low class according to their material situation. Actually, the eternal soul exists beyond material duality but falsely mistakes the material situation to be his own. The words asaj-jana-kṛd yathā are significant. A father may by nature be peaceful, but because his bad son gets into trouble the father is forced to defend his son and consider his son’s enemies to be enemies of the entire family. Thus the bad son implicates the father in troublesome conflicts. Similarly, the spirit soul has no intrinsic problems, but by creating a false identification with the material body the soul becomes involved in the happiness and distress of the body. With this verse the Lord summarizes His discussion of the difference between the body and the soul.