Srimad Bhagavatam Canto 11, Chapter 21, Text 21

SB 11.21.21

taya virahitah sadho
 jantuh sunyaya kalpate
tato ’sya svartha-vibhramso
 murcchitasya mrtasya ca
 
Translation: 
 
O saintly Uddhava, a person bereft of real intelligence is considered to have lost everything. Deviated from the actual purpose of his life, he becomes dull, just like a dead person.
 
Purport: 
 
Krsna consciousness is so vital and essential that one who has deviated from this progressive path of self-realization is considered to be virtually unconscious, or like a dead person. Since every living entity is part and parcel of Krsna, anyone who falsely identifies with the external body is actually unconscious of his real position. Thus it is stated, sunyaya kalpate: pursuing that which has no factual existence, he is devoid of any tangible progress or benefit in life. One whose consciousness is absorbed in the nonexistent becomes himself practically nonexistent. In this way, the eternal living entities become fallen, lost in the ocean of material existence, and it is only by the special mercy of the pure devotees of the Lord that they can be rescued. The Lord’s devotees therefore instruct the fallen people to chant Hare Krsna, Hare Krsna, Krsna Krsna, Hare Hare/ Hare Rama, Hare Rama, Rama Rama, Hare Hare. By this process our real consciousness and life can be quickly revived.
Srimad Bhagavatam Canto 11, Chapter 21, Text 20
Srimad Bhagavatam Canto 11, Chapter 21, Text 22