"When a person becomes attracted by Kṛṣṇa and is in full Kṛṣṇa consciousness, he does not care for any worldly duties, even though very urgent. Kṛṣṇa consciousness is so powerful that it gives everyone relief from all material activities. Śrīla Rūpa Gosvāmī has written a very nice verse wherein one gopī advises another, 'My dear friend, if you desire to enjoy the company of material society, friendship and love, then please do not go to see this smiling boy Govinda, who is standing on the bank of the Yamunā and playing His flute, His lips brightened by the beams of the full moonlight.' Śrīla Rūpa Gosvāmī indirectly instructs that one who has been captivated by the beautiful smiling face of Kṛṣṇa has lost all attraction for material enjoyments. This is the test of advancement in Kṛṣṇa consciousness: a person advancing in Kṛṣṇa consciousness must lose interest in material activities and personal sense gratification."
(Kṛṣṇa Book, Chapter 29)
"The test of the real change of heart that takes place when one chants the Hare Kṛṣṇa mahā-mantra is that one becomes detached from material enjoyment. This is the real change. Bhaktiḥ pareśānubhavo viraktir anyatra ca (SB 11.2.42). If one is actually advancing in spiritual life, he must become very much detached from material enjoyment. If it is sometimes found that a kaniṣṭha-adhikārī (neophyte devotee) shows artificial tears in his eyes while chanting the Hare Kṛṣṇa mantra but is still completely attached to material things, his heart has not really changed. The change must be manifested in terms of one’s real activities."
(Caitanya-caritāmṛta Ādi 8.25, Purport)
"On the mahā-bhāgavata platform, the devotee makes no distinction between friends and enemies. On that platform he sees everyone as a servant of Kṛṣṇa. As stated in the Bhagavad-gītā (BG 5.18):
vidyā-vinaya-sampanne brāhmaṇe gavi hastini
śuni caiva śva-pāke ca paṇḍitāḥ sama-darśinaḥ
'The humble sages, by virtue of true knowledge, see with equal vision a learned and gentle brāhmaṇa, a cow, an elephant, a dog, and a dog-eater [outcaste].' A mahā-bhāgavata, being learned and advanced in spiritual consciousness, sees no difference between a tiger, an elephant or a learned scholar. The test of advanced spiritual consciousness is that one becomes fearless. He envies no one, and he is always engaged in the Lord’s service. He sees every living entity as an eternal part and parcel of the Lord, rendering service according to his capacity by the will of the Supreme Lord."
(Caitanya-caritāmṛta Madhya 17.31, Purport)
"Happiness and distress are concommitant factors of material life. One should learn to tolerate, as advised in Bhagavad-gītā. One can never restrict the coming and going of happiness and distress, so one should be detached from the materialistic way of life and be automatically equiposed in both cases. Generally, when we get something desirable, we are very happy, and when we get something undesirable, we are distressed. But if we are actually in the spiritual position, these things will not agitate us. To reach that stage, we have to practice unbreakable devotional service; devotional service to Kṛṣṇa without deviation means engaging oneself in the nine processes of devotional service, chanting, hearing, worshiping, offering respect, etc., as described in the last verse of the Ninth Chapter. That process should be followed. Naturally, when one is adapted to the spiritual way of life, he will not want to mix with materialistic men. That would go against his grain. One may test himself by seeing how far he is inclined to live in a solitary place without unwanted association."
(Bhagavad-gītā As It Is 13.8-12, Purport)
"This Kṛṣṇa consciousness, or bhakti, devotional service, means to develop attachment for Kṛṣṇa, and in the same proportion develop detachment for material sense gratification. Two things cannot go on. Just like here is a glass containing water. If you want to put milk in this glass, then you have to throw away the water. If you think that, 'I shall keep half water, half milk,' that can be done, but both of them becomes diluted or polluted. If you want to keep milk, then you have to throw out the water, and if you want to keep water, then you cannot keep milk. Similarly, bhakti pareśānubhavaḥ. This is the test. If you become Kṛṣṇa conscious, if you are improving in your spiritual life, proportionately you will be detached from materialistic way of life. That is the test."
(Srila Prabhupada Lecture, Los Angeles, December 13, 1968)
"So to become Kṛṣṇa conscious means immediately—that is the test—immediately he will become free from lust and greediness. If he's not free from lust and greediness, he is making a show; he's not Kṛṣṇa conscious. This is the test. If one is actually advanced in Kṛṣṇa consciousness, then these two symptoms will be visible in his character: no more lusty, no more greediness."
(Srila Prabhupada Lecture, Los Angeles, August 22, 1972)
"Those who are jealous and envious, they are within this material world. And those who are not jealous, they are in the spiritual world. Simple thing. You test yourself, 'Whether I am jealous, envious of my other associates, friends, everything?' Then I am in the material world. And if I am not jealous, then I'm in the spiritual world. Anyone can test. There is no question of whether I'm spiritually advanced or not. You can test yourself. Bhaktiḥ pareśānubhavo viraktir anyatra syāt (SB 11.2.42). Just like if you are eating, you'll understand whether you are satisfied, whether your hunger is satisfied. You haven't got to take certificate from others. Similarly, if you test yourself whether you are jealous, whether you are envious, then you are in the material world. And if you are not jealous, if you are not envious, then in the spiritual world. Then you can serve Kṛṣṇa very nicely if you are not jealous. Because our jealous, enviousness has begin, began from Kṛṣṇa."
(Srila Prabhupada Lecture, Los Angeles, April 15, 1973)
"Those who are spiritually realized, they will find to serve Kṛṣṇa means new enlightenment. New enlightenment. Nava-nava-rasa-dhāmany udyataṁ rantum āsīt. Here in this material world, you enjoy, it becomes hackneyed. Punaḥ punaś carvita (SB 7.5.30). Therefore you are disappointed. But if you engage yourself in the service of Kṛṣṇa, you'll find new and new encouragement. That is spiritual. If you find it hackneyed, then you must know that you are not yet serving spiritually, you are serving materially. Formality, stereotype. But if you feel new and new energy, then you know that you are serving spiritually. This is the test. Your enthusiasm will increase, not decrease. So the test is within our hand."
(Srila Prabhupada Lecture, London, August 26, 1973)
"So this is the process of the more you become purified, the more you'll be advanced in Kṛṣṇa consciousness. And your advancement in Kṛṣṇa consciousness will be tested, how you are developing good qualities. Officially I'm Kṛṣṇa conscious yogī, but I am still addicted to so many nonsense habits—that means you are not advancing. That is the test. Yasyāsti bhaktir bhagavaty akiñcanā sarvair guṇais tatra samāsate (SB 5.18.12). He hasn't got to learn how to become good. Simply by executing this devotional service, he'll be all-good. That is the test."
(Srila Prabhupada Lecture, San Diego, July 1, 1972)
"This should be practiced, you see—reducing eating, sleeping, mating; there is spiritual advancement. This is the test. The more you reduce, the ideal is to bring it to nil. Just like Gosvāmīs, they did it. Nidrāhāra-vihārakādi-vijitau (Śrī Śrī Ṣaḍ Gosvāmy Aṣṭaka), they conquered over sleeping and eating and mating. Conquered over. So our ideal is we are fighting with māyā, so the fighting will conquer over māyā when we see that we are not disturbed by these four processes: eating, sleeping, mating and defending. This is the test. Nobody has to take certificate from anyone as how he is spiritually advancing. He can test himself: 'How far I have conquered over these four things: eating, sleeping, mating and defending.' That's all. That is the test. So it is not required that don't eat, don't sleep, don't... but minimize it, at least regulate it. Try. This is called austerity, tapasya. I want to sleep, but still I shall regulate it. I want to eat, but I must regulate it. I want sense enjoyment, so I must regulate it. That is old Vedic civilization."
(Srila Prabhupada Lecture, London, August 23, 1971)
"Phalena paricīyate. By the result you can understand. By service (to) Kṛṣṇa, he will understand more about Kṛṣṇa. Kṛṣṇa will be clear to him. That is the test. Because it is said, sevonmukhe hi jihvādau svayam (CC Madhya 17.136). Kṛṣṇa cannot be realized by so-called speculation, but if you render service to Kṛṣṇa, then Kṛṣṇa will reveal to you. Revelation. So he, how much service he is giving, that will be tested how much he has, I mean to say, realized Kṛṣṇa. This is the test. If Kṛṣṇa is still vague idea to him, then he has not advanced. This is the test. Just like if you have eaten something, then you will feel satisfaction. You are hungry, you have been given some food, but you cannot say that, 'I am eating, also I am not satisfied in my hunger.' That cannot be. If you are actually serving Kṛṣṇa, then Kṛṣṇa will reveal to you. You will know what is Kṛṣṇa, asaṁśayaṁ samagraṁ mām, without any doubt, and fullness. Here is the test."
(Srila Prabhupada Lecture, Melbourne, June 29, 1974)
"So everyone has to test himself that 'How far I have advanced?' That means 'How far I have become detached with material contamination.' That's all. The test is in your hand. And if you are sincere, then you should test yourself. And if you want to make show, that is a different thing. That is explained in the Second Chapter, sthita-prajña. The behavior of a person who has advanced in spiritual consciousness, that is explained. You have studied. He talks like that, he walks like that, he behaves like that. So many things, they have been explained. These are the test. So we may not be able to achieve all the success immediately, but everyone should try to follow."
(Srila Prabhupada Lecture, Los Angeles, December 20, 1968)
"Everyone in this material world, we are suffering the sinful reaction of our past life or this life. That is a fact. But Kṛṣṇa says that, 'I can give you protection from all reaction of sinful life if you surrender unto Me.'
So to become free from sinful life, there is only simple method: if you surrender to Kṛṣṇa. That is the beginning of bhakti. Yato bhaktir adhokṣaje. Bhakti life begins when you fully surrender unto the lotus feet of God. That is the bhakti life. So here it is said that it does not matter whether you are a Hindu or Muslim or Christian or Buddhist. It doesn't matter. Your system of religion is first class if you can develop your general love for Kṛṣṇa, or God, Adhokṣaja. That is the test. You may advertise yourself or I may advertise myself, 'I am a great religious person,' but the test is how much you have learned to love God, how much you have advanced in that process."
(Srila Prabhupada Lecture, Delhi, November 11, 1973)
"In Bengal there is a proverb: bhajana kara, pūjāna kara, mate janle haya. Your devotional service will be tested at the time of death. Because yaṁ yaṁ vāpi smaram loke tyajaty ante kalevaram. At the time of death, if we can remember Kṛṣṇa, Nārāyaṇa-smṛtiḥ, that is all success. The practice of devotional service means so that we may be so accustomed to chanting Hare Kṛṣṇa mantra that at the time of death we may remember it. Otherwise... Not like parrot. The parrot also imitates chanting. But when the cat catches, he does not say, 'Hare Kṛṣṇa.' He says (imitates parrot sound), "kanh, kanh." So not that kind of... We should be accustomed to chant Hare Kṛṣṇa that whenever the death point is there, he would chant Hare Kṛṣṇa, Hare Kṛṣṇa. Then that is success. So practice means to remember. Sadā tad-bhāva-bhāvitaḥ (BG 8.6). If we practice always thinking of Kṛṣṇa, naturally, at the time of danger, we shall chant Hare Kṛṣṇa."
(Srila Prabhupada Lecture, Vrindavan, November 14, 1972)