The definition of a pure devotee, as given by Rūpa Gosvāmī in his Bhakti-rasāmṛta-sindhu, can be summarized thus: his service is favorable and is always in relation to Kṛṣṇa. In order to keep the purity of such Kṛṣṇa conscious activities, one must be freed from all material desires and philosophical speculation. Any desire except for the service of the Lord is called material desire. And “philosophical speculation” refers to the sort of speculation which ultimately arrives at a conclusion of voidism or impersonalism. This conclusion is useless for a Kṛṣṇa conscious person. Only rarely by philosophical speculation can one reach the conclusion of worshiping Vāsudeva, or Kṛṣṇa. This is confirmed in the Bhagavad-gītā itself. The ultimate end of philosophical speculation, then, must be Kṛṣṇa, with the understanding that Kṛṣṇa is everything, the cause of all causes, and that one should therefore surrender unto Him. If this ultimate goal is reached, then philosophical advancement is favorable, but if the conclusion of philosophical speculation is voidism or impersonalism, that is not bhakti.

Karma, or fruitive activities, is sometimes understood to consist of ritualistic activities. There are many persons who are very much attracted by the ritualistic activities described in the Vedas. But if one becomes attracted simply to ritualistic activities without understanding Kṛṣṇa, his activities are unfavorable to Kṛṣṇa consciousness. Actually, Kṛṣṇa consciousness can be based simply on hearing about Kṛṣṇa, chanting about Him, remembering Him, etc. The Śrīmad-Bhāgavatam describes nine different processes, besides which everything done is unfavorable to Kṛṣṇa consciousness.

Śrīla Rūpa Gosvāmī has also quoted a definition from the Nārada Pañcarātra, as follows: “One should be free from all material designations and, by Kṛṣṇa consciousness, must be cleansed of all material contamination. He should be restored to his pure identity, in which he engages his senses in the service of the proprietor of the senses.” So when our senses are engaged for Kṛṣṇa, the actual proprietor of the senses, that activity is called devotional service. In our conditioned state our senses are engaged in serving the bodily demands. When the same senses are engaged in executing the order of Kṛṣṇa, our activities are called bhakti.

As long as one identifies himself as belonging to a certain family, a certain society, or a certain nation, he is said to be covered with designations. When one is fully aware that he does not belong to any family, society, or country but is eternally related to Kṛṣṇa, he then realizes that his energy should be employed not in the interests of so-called family, society, or country but in the interests of Kṛṣṇa. This is purity of purpose and the platform of pure devotional service in Kṛṣṇa consciousness.