The devotees are actually saintly persons, or sādhus. The first qualification of a sādhu, or devotee, is ahiṁsā, or nonviolence. Persons interested in the path of devotional service, or in going back home, back to Godhead, must first practice ahiṁsā, or nonviolence. A sādhu is described as titikṣavaḥ kāruṇikāḥ (SB 3.25.21). A devotee should be tolerant and should be very much compassionate toward others. For example, if he suffers personal injury, he should tolerate it, but if someone else suffers injury, the devotee need not tolerate it. The whole world is full of violence, and a devotee's first business is to stop this violence, including the unnecessary slaughter of animals. A devotee is the friend not only of human society but of all living entities, for he sees all living entities as sons of the Supreme Personality of Godhead. He does not claim himself to be the only son of God and allow all others to be killed, thinking that they have no soul. This kind of philosophy is never advocated by a pure devotee of the Lord. Suhṛdaḥ sarva-dehinām: a true devotee is the friend of all living entities. Kṛṣṇa claims in Bhagavad-gītā to be the father of all species of living entities; consequently the devotee of Kṛṣṇa is always a friend of all. This is called ahiṁsā. Such nonviolence can be practiced only when we follow in the footsteps of great ācāryas. Therefore, according to our Vaiṣṇava philosophy, we have to follow the great ācāryas of the four sampradāyas, or disciplic successions.
Trying to advance in spiritual life outside the disciplic succession is simply ludicrous. It is said, therefore, ācāryavān puruṣo veda: one who follows the disciplic succession of ācāryas knows things as they are (Chāndogya Upaniṣad 6.14.2). Tad-vijñānārthaṁ sa gurum evābhigacchet: [MU 1.2.12] in order to understand the transcendental science, one must approach the bona fide spiritual master. The word smṛtyā is very important in spiritual life. Smṛtyā means remembering Kṛṣṇa always. Life should be molded in such a way that one cannot remain alone without thinking of Kṛṣṇa. We should live in Kṛṣṇa so that while eating, sleeping, walking and working we remain only in Kṛṣṇa. Our Kṛṣṇa consciousness society recommends that we arrange our living so that we can remember Kṛṣṇa. In our ISKCON society the devotees, while engaged in making Spiritual Sky incense, are also hearing about the glories of Kṛṣṇa or His devotees. The śāstra recommends, smartavyaḥ satataṁ viṣṇuḥ: Lord Viṣṇu should be remembered always, constantly. Vismartavyo na jātucit: Viṣṇu should never be forgotten. That is the spiritual way of life. Smṛtyā. This remembrance of the Lord can be continued if we hear about Him constantly. It is therefore recommended in this verse: mukundācaritāgrya-sīdhunā. Sīdhu means "nectar." To hear about Kṛṣṇa from Śrīmad-Bhāgavatam or Bhagavad-gītā or similar authentic literature is to live in Kṛṣṇa consciousness. Such concentration in Kṛṣṇa consciousness can be achieved by persons who are strictly following the rules and regulative principles. We have recommended in our Kṛṣṇa consciousness movement that a devotee chant sixteen rounds on beads daily and follow the regulative principles. That will help the devotee be fixed in his spiritual advancement in life.
It is also stated in this verse that one can advance by controlling the senses (yamaiḥ). By controlling the senses, one can become a svāmī or gosvāmī. One who is therefore enjoying this supertitle, svāmī or gosvāmī, must be very strict in controlling his senses. Indeed, he must be master of his senses. This is possible when one does not desire any material sense gratification. If, by chance, the senses want to work independently, he must control them. If we simply practice avoiding material sense gratification, controlling the senses is automatically achieved.
Another important point mentioned in this connection is anindayā—we should not criticize others' methods of religion. There are different types of religious systems operating under different qualities of material nature. Those operating in the modes of ignorance and passion cannot be as perfect as that system in the mode of goodness. In Bhagavad-gītā everything has been divided into three qualitative divisions; therefore religious systems are similarly categorized. When people are mostly under the modes of passion and ignorance, their system of religion will be of the same quality. A devotee, instead of criticizing such systems, will encourage the followers to stick to their principles so that gradually they can come to the platform of religion in goodness. Simply by criticizing them, a devotee's mind will be agitated. Thus a devotee should tolerate and learn to stop agitation.
Another feature of the devotee is nirīhayā, simple living. Nirīhā means "gentle," "meek" or "simple." A devotee should not live very gorgeously and imitate a materialistic person. Plain living and high thinking are recommended for a devotee. He should accept only so much as he needs to keep the material body fit for the execution of devotional service. He should not eat or sleep more than is required. Simply eating for living, and not living for eating, and sleeping only six to seven hours a day are principles to be followed by devotees. As long as the body is there it is subjected to the influence of climatic changes, disease and natural disturbances, the threefold miseries of material existence. We cannot avoid them. Sometimes we receive letters from neophyte devotees questioning why they have fallen sick, although pursuing Kṛṣṇa consciousness. They should learn from this verse that they have to become tolerant (dvandva-titikṣayā). This is the world of duality. One should not think that because he has fallen sick he has fallen from Kṛṣṇa consciousness. Kṛṣṇa consciousness can continue without impediment from any material opposition. Lord Śrī Kṛṣṇa therefore advises in Bhagavad-gītā (BG 2.14), tāṁs titikṣasva bhārata: "My dear Arjuna, please try to tolerate all these disturbances. Be fixed in your Kṛṣṇa conscious activities."