1.) March 1 1975 Atlanta conversations — One who is completely free from all sinful activities, they can become pure devotee. So even after becoming free from sinful activities, if one has got some motive, then he is also not pure devotee. Pure devotee means without any material motive: "God is great. I am His subordinate. I must love God. I must render service to God." This is pure devotee. And if I go to God, "Please give me my bread," that is not pure devotee, because he has got some purpose. As soon as his purpose is fulfilled, he may turn nondevotee. Just like one of my German Godbrothers said that in Germany during the last war, Second World War, many women used to go to the church to pray to God to get back their husband, son, or brother. But nobody came back. And they became atheist: "There is no God. We prayed so much, and my father did not come, my brother did not come, my son did not come." So motivated devotion is sometimes frustrated, and they become atheist.
2.) Feb 25 1975 room conversation-
Rāmeśvara: Just like this Alice Coltrane. She has done her small part. She made this record album with Govinda Jaya Jaya and Hare Kṛṣṇa.
Prabhupāda: That is… That will be a good thing. But when he (she) does it properly it will be more effective, because there is… If one does not chant in the process, then gradually it degrades. The offense will increase. There is chance.
3.)Madhya 19.160 — "If one does not distinguish between the bhakti-latā creeper and the other creepers, the sprinkling of water is misused because the other creepers are nourished while the bhakti-latā creeper is curtailed.
PURPORT – If one chants the Hare Kṛṣṇa mantra while committing offenses, these unwanted creepers will grow. One should not take advantage of chanting the Hare Kṛṣṇa mantra for some material profit. As mentioned in verse 159:'niṣiddhācāra', 'kuṭīnāṭī', jīva-hiṁsana' 'lābha', 'pūjā', 'pratiṣṭhādi' yata upaśākhā-gaṇa
The unwanted creepers have been described by Śrīla Bhaktisiddhānta Sarasvatī Ṭhākura. He states that if one hears and chants without trying to give up offenses, one becomes materially attached to sense gratification. One may also desire freedom from material bondage like the Māyāvādīs, or one may become attached to the yoga-siddhis and desire wonderful yogic powers. If one is attached to wonderful material activities, one is called siddhi-lobhī, greedy for material perfection. One may also be victimized by diplomatic or crooked behavior, or one may associate with women for illicit sex. Others may make a show of devotional service like the prākṛta-sahajiyās, or one may try to support his philosophy by joining some caste or identifying himself with a certain dynasty, claiming a monopoly on spiritual advancement. Thus with the support of family tradition, one may become a pseudo guru or so-called spiritual master. One may become attached to the four sinful activities-illicit sex, intoxication, gambling and meat eating, or one may consider a Vaiṣṇava to belong to a mundane caste or creed. One may think, "This is a Hindu Vaiṣṇava, and this is a European Vaiṣṇava. A European Vaiṣṇava is not allowed to enter the temples." In other words, one may consider Vaiṣṇavas in terms of birth, thinking one a brāhmaṇa Vaiṣṇava, a śūdra Vaiṣṇava, a mleccha Vaiṣṇava and so on. One may also try to carry out a professional business while chanting the Hare Kṛṣṇa mantra or reading Śrīmad-Bhāgavatam, or one may try to increase his monetary strength by illegal means. One may also try to be a cheap Vaiṣṇava by chanting in a secluded place for material adoration, or one may desire mundane reputation by making compromises with nondevotees, compromising one's philosophy or spiritual life, or one may become a supporter of a hereditary caste system. All these are pitfalls of personal sense gratification. Just to cheat some innocent people, one makes a show of advanced spiritual life and becomes known as a sādhu, mahātmā or religious person. All this means that the so-called devotee has become victimized by all these unwanted creepers and that the real creeper of bhakti-latā-bīja has been stunted.