Bg 3.32

ye tv etad abhyasūyanto
nānutiṣṭhanti me matam
sarva-jñāna-vimūḍhāṁs tān
viddhi naṣṭān acetasaḥ
Synonyms: 
ye — those; tu — however; etat — this; abhyasūyantaḥ — out of envy; na — do not; anutiṣṭhanti — regularly perform; me — My; matam — injunction; sarva-jñāna — in all sorts of knowledge; vimūḍhān — perfectly befooled; tān — they are; viddhi — know it well; naṣṭān — all ruined; acetasaḥ — without Kṛṣṇa consciousness.
Translation: 
But those who, out of envy, disregard these teachings and do not follow them regularly are to be considered bereft of all knowledge, befooled, and ruined in their endeavors for perfection.
Purport: 

The flaw of not being Kṛṣṇa conscious is clearly stated herein. As there is punishment for disobedience to the order of the supreme executive head, so there is certainly punishment for disobedience to the order of the Supreme Personality of Godhead. A disobedient person, however great he may be, is ignorant of his own self, and of the Supreme Brahman, Paramātmā and the Personality of Godhead, due to a vacant heart. Therefore there is no hope of perfection of life for him.