Give up the shackles of matter slowly. Cultivate your spirit inwards. Give up prejudices which you have acquired from the so-called rational thinkers who deny the existence of spirit. Be humble in your self and learn to respect those who work towards spiritual attainments. Do these with your heart, mind, and strength in the company of spiritual people alone, and you will see Krsna in no time.
(Srila Bhaktivinoda Thakura,Sri Caitanya Mahaprabhu, His Life and Precepts)
There is no stronger obstruction to one's self interest than thinking other subject matters to be more pleasing than one's self-realization.
(Sanat Kumara, Srimad-Bhagavatam 4.22.32)