Srimad Bhagavatam Canto 11, Chapter 23, Text 48

SB 11.23.48

tam durjayam satrum asahya-vegam
 arun-tudam tan na vijitya kecit
kurvanty asad-vigraham atra martyair
 mitrany udasina-ripun vimudhah
 
Translation: 
 
Failing to conquer this irrepressible enemy, the mind, whose urges are intolerable and who torments the heart, many people are completely bewildered and create useless quarrel with others. Thus they conclude that other people are either their friends, their enemies or parties indifferent to them.
 
Purport: 
 
Falsely identifying oneself as the material body, and accepting bodily expansions such as children and grandchildren to be one’s eternal property, one completely forgets that every living being is qualitatively one with God. There is no essential difference between one individual being and another, since all are eternal expansions of the Supreme Lord. The mind absorbed in false ego creates the material body, and by identification with the body, the conditioned soul is overwhelmed by false pride and ignorance, as described here.
Srimad Bhagavatam Canto 11, Chapter 23, Text 47
Srimad Bhagavatam Canto 11, Chapter 23, Text 49