"How you will get peace of mind? Here in the material world you cannot be endowed with the peace of mind. It is not possible. Why? Because here everything is māyā. Bharam udvahato vimūḍhān. Asad-grahāt, sadā samudvigna-dhiyām asad-grahāt (SB 7.5.5). Asat. Asat means that which will not stand. The material nature is like that. It will not stand. This body we have got at a certain date, and it will continue up to certain date, then it will vanish. You will get never again this body. Finished. So this is called asat. Asato mā sad gama. This is Vedic instruction: 'Don't remain in the asat, temporary.' Sad gama: 'Come to the platform of eternity.'"
(Srila Prabhupada Lecture, Bombay, December 31, 1974)
"Everyone, so many people, come to us. Their first question is that 'I am not getting peace in my mind. How can I get peace?' Yes, how can you get peace? You have no connection with the Supreme Person. Kuto śānty ayuktasya, in the Bhagavad-gītā it is... How you can get peace? It is impossible.
Many examples we have given many times. A child is crying. Everyone is trying to pacify the child—still crying. But as soon as the mother takes the child on the breast, immediately pacified. This is the... You are searching after peace life after life, moment after mo..., hour after... You cannot have peace unless you come to the Supreme Personality of Godhead. It is not possible. Therefore it is advised, tasyaiva hetoḥ prayateta kovido (SB 1.5.18). For that purpose, how you can see God or you can please God, tasyaiva, hetoḥ, for that purpose only, prayateta, one should endeavor. No other endeavor. Human life is meant for... That is Vedānta-sūtra. Athāto brahma jijñāsā. Where is Brahman? Where is the Absolute Truth? Where is God?"
(Srila Prabhupada Lecture, Vrindavan, April 8, 1976)
"Just like you can see in reality that these boys, these girls who have joined this Kṛṣṇa consciousness movement, because they are reading Śrīmad-Bhāgavatam, Bhagavad-gītā, they are now gradually realizing what is God and what is his relationship with God. So unless we realize God and our position, and we become lover of God, there is no question of peace in the mind. Therefore it is recommended here that if you want real peace in the mind, try to understand what is God, what is your relationship with God, and act accordingly. You will be immediately peaceful. As soon as you become peaceful, your life is successful."
(Srila Prabhupada Lecture, Caracas, February 23, 1975)
"Everyone is seeking peace of mind. People come to spiritual societies or some other way, everyone is searching after some peace, śāntam. Śānti. The śānti can be attained when this sattva-guṇaṁ svaccham, when the sattva-guṇa, your status will be on the sattva-guṇa and completely cleansed. Then you can get śānti. Completely cleansed means... That is explained in the Bhagavad-gītā, na śocati na kāṅkṣati: 'There is no lamentation and there is no hankering.' Then it is śānti. As soon as there is some hankering, you cannot have śānti. That is not possible. And as soon as there is some possession, you cannot be without lamentation. The two things, material, they are ruling over us. We are hankering after something which we do not possess, and what we possess, if it is lost, then we are lamenting. So śānti means no hankering, no lamenting. That is called śānti."
(Srila Prabhupada Lecture, Bombay, December 30, 1974)
"You have to come to the platform of sattva-guṇa. Then you'll be prasannātmā. Prasanna means happy mode of life. Brahma-bhūtaḥ prasannātmā. What is the happy mode of life? Na śocati na kāṅkṣati. He does not lament. He does not hanker. Here in the material world we are hankering. We want this dhanaṁ dehi rūpaṁ dehi yaśo dehi rūpavatī bhāryāṁ dehi. Dehi dehi. That is hankering. This is not the stage of brahma-bhūta. Brahma-bhūta stage means na śocati na kāṅkṣati. He does not hanker, neither he laments. Then samaḥ sarveṣu bhūteṣu mad-bhaktiṁ labhate parām (BG 18.54). Then bhakti begins, when actually you are in peace of mind. In disturbed mind you cannot execute devotional service."
(Srila Prabhupada Lecture, Calcutta, September 27, 1974)
"It is a false idea that one will be satisfied or be happy simply by economic development. No, that is not possible, practically. In your country, America, there is immense economic development, but you could not get any happiness. That is not possible. Happiness will be possible when, first of all, you are situated in the brahminical position, sattva-guṇa; and to come to that brahminical position, you have to give up the activities of rajas-tamo-guṇa. The rajas-tamo-guṇa is that illicit sex, meat-eating, intoxication and gambling. That's all. So if you voluntarily give up, and be situated in the sattva-guṇa, then you'll be happy."
(Srila Prabhupada Lecture, Vrindavan August 9, 1974)
"Absence of war is not peace. Just think over. Suppose now there is no war. Do you think that everybody is in peace? Ask any individual person that 'Are you in peace? Are you in peace of mind or peace of...' No war is not only the cause. There are many other causes which disturbs our peace. War is one of the causes. So simply if you stop war that does not mean peace is guaranteed. No. War is one of the disturbing things of peace. But there are many other disturbing things, many, incalculable, which will disturb you. You see? So we have to take relief from all disturbing position. War is one of the items. And that can be done when you are Kṛṣṇa conscious."
(Srila Prabhupada Lecture, New York, August 5, 1966)
"The final conclusion in the Bhagavad-gītā is that if you want to be peaceful, if you want the peace of your mind, you should understand three things. That three things are that to understand that God is the supreme enjoyer. This is one. He is the proprietor of everything, and He is friend of everyone. If you learn these three things only, very scientifically, that God is the proprietor, God is the enjoyer and God is the supreme friend of everyone, then your life is successful. And these simple things will be understood by you by chanting God's name: Hare Kṛṣṇa, Hare Kṛṣṇa, Kṛṣṇa Kṛṣṇa, Hare Hare/ Hare Rāma, Hare Rāma, Rāma Rāma, Hare Hare."
(Srila Prabhupada Festival Lecture, Paris, June 14, 1974)
"It is quite evident that you are feeling anxiety in your mind. The best way to overcome this, the way to control the mind is to become Krsna conscious. This is stated in the Bhagavad gita in the sixth chapter, that one has to control the mind otherwise the mind will become his worst enemy. The process for Krsna consciousness is that we control the mind through hearing and chanting. We hear the maha mantra, Hare Krsna Hare Krsna Krsna Krsna Hare Hare Hare Rama Hare Rama Rama Rama Hare Hare and we hear the lectures from the spiritual master and read his books. Also we speak by preaching and by chanting. This is the easy method for controlling the mind, by hearing and chanting.
So my advice to you is to somehow or other fix your mind on Krsna then you will experience peace of mind and your mind will be your best friend."
(Srila Prabhupada Letter, September 4, 1975)