(Unless one is very fortunate, he cannot come to the shelter of Kṛṣṇa consciousness. That's a fact. So don't misuse it. That is my request) 



Ei rūpe brahmāṇḍa bhramite kono bhāgyavān jīva (CC Madhya 19.151).
It is great fortune, bhāgyavan jīva. Unless one is very fortunate, he cannot come to the shelter of Kṛṣṇa consciousness. That's a fact. So don't misuse it. That is my request. I am very glad to see you, you are so enthusiastic. And you should be enthusiastic."
(His Divine Grace A.C.Bhaktivedanta Swami Srila Prabhupada Lecture, April 27, 1976, Auckland)
Comments
When we do something in the mood of ; let me gain, let me improve things for myself, then it is karmic, that's fine, but that selfish thought often becomes sin, due to greed, with bad consequences for all, including bondage.
When we do something in the mood of ; I am God's servant, out of love and duty, let me serve all His creaures to my best capacity always; then this is spiritual, and will lead to the best results for everyone, including perfect liberation !