Srimad Bhagavatam Canto 11, Chapter 02, Text 38

SB 11.2.38

avidyamano ’py avabhati hi dvayo
dhyatur dhiya svapna-manorathau yatha
tat karma-sankalpa-vikalpakam mano
budho nirundhyad abhayam tatah syat
Translation by His Divine Grace A. C. Bhaktivedanta Swami Srila Prabhupada: 
Although the duality of the material world does not ultimately exist, the conditioned soul experiences it as real under the influence of his own conditioned intelligence. This imaginary experience of a world separate from Krsna can be compared to the acts of dreaming and desiring. When the conditioned soul dreams at night of something desirable or horrible, or when he daydreams of what he would like to have or avoid, he creates a reality that has no existence beyond his own imagination. The tendency of the mind is to accept and reject various activities based on sense gratification. Therefore an intelligent person should control the mind, restricting it from the illusion of seeing things separate from Krsna, and when the mind is thus controlled he will experience actual fearlessness.
Purport by His Divine Grace A. C. Bhaktivedanta Swami Srila Prabhupada: 
Although the conditioned mind is bewildered by the objects of sense gratification offered by maya, illusion, if one takes to the unalloyed devotional service of the Lord such material sense gratification gradually dissipates, for it is merely a mental concoction of the conditioned soul. Srila Sridhara Svami has emphasized by the words avyabhicarini bhakti that one cannot dissipate the illusion of material sense gratification unless one takes to the unalloyed devotional service of the Lord. As Srila Rupa Gosvami has stated:
anukulyena krsnanu-
silanam bhaktir uttama
(Bhakti-rasamrta-sindhu 1.1.11)
Unalloyed devotional service cannot be mixed with material sense gratification or mental speculation. The servant must act only for the satisfaction of the master. Similarly, Lord Krsna states in Bhagavad-gita, mam ekam saranam vraja. One must see only Krsna everywhere and must act exclusively for the satisfaction of Lord Krsna, the eternal master of every living entity.
Srila Madhvacarya has quoted several verses from the Hari-vamsa illustrating that the living entity bewildered by identifying with his material body, home, family, friends and so on and thus entangled in the cycle of birth and death accepts phantasmagoria as reality. According to Srila Jiva Gosvami, sravana-kirtanadi-laksana-matratvam yato na vyahanyeta: if one seriously desires to vanquish the duality of material illusion, one must adopt the process of chanting and hearing the glories of the Supreme Lord. Sri Caitanya Mahaprabhu also cited the following Vedic reference:
harer nama harer nama
harer namaiva kevalam
kalau nasty eva nasty eva
nasty eva gatir anyatha
(Brhan-naradiya Purana)
According to Vedic literatures the living entities of this Kali-yuga are very feeble in their power to understand spiritual knowledge (mandah sumanda-matayo manda-bhagya hy upadrutah). Their minds are always disturbed, and they are lazy and misguided by so many bogus leaders. They are further described in the Bhagavatam as nihsattvan (impatient and impious), durmedhan (possessed of weak intelligence) and hrasitayusah (very short lived). Therefore one who seriously wants to overcome the ignorance of material life must surrender to the process of chanting and hearing the holy name of the Lord Hare Krsna, Hare Krsna, Krsna Krsna, Hare Hare/ Hare Rama, Hare Rama, Rama Rama, Hare Hare as well as reciting and rendering submissive aural reception to the transcendental literatures presented by the Lord, such as Bhagavad-gita, Srimad-Bhagavatam and Caitanya-caritamrta. It should be understood that the living entity is completely spiritual and never actually becomes mixed with material energy (asango hy ayam purusah). According to Srila Jiva Gosvami, tasmin suddhe ’pi kalpyate: although the living entity is suddha, pure spirit soul, he imagines that he is a material creation and thus entangles himself in the network of illusion called dehapatya-kalatradi.
Srila Visvanatha Cakravarti Thakura has used the word manasa-pratyaksa to describe the experience of material life. Manasa-pratyaksa means “that which is experienced only within the mind.” The actual pratyaksa is described in Bhagavad-gita (9.2):
raja-vidya raja-guhyam
pavitram idam uttamam
pratyaksavagamam dharmyam
susukham kartum avyayam
When one submissively hears the instructions given by the Lord Himself in Bhagavad-gita, which constitute the king of all knowledge (raja-vidya) and the most confidential of all information (raja-guhyam), by associating with such spotless spiritual knowledge (pavitram idam uttamam) one can directly experience one’s eternal nature (pratyaksavagamam). By experiencing one’s eternal nature, one becomes thoroughly religious (dharmyam), blissful (susukham) and eternally engaged in the devotional service of the Lord (kartum avyayam).
Srila Visvanatha Cakravarti Thakura has quoted the following sruti-mantra in this connection: vijita-hrsika-vayubhir adanta-manas turagam. “By the very senses and life air one has conquered, the uncurbed mind will again drag one away.” According to Srila Visvanatha Cakravarti Thakura the meaning of this verse is samavahaya guros caranam: if one rejects the lotus feet of one’s spiritual master, all of one’s previous spiritual advancement becomes null and void. This has already been indicated in the previous verse by the words guru-devatatma. Unless one accepts a bona fide spiritual master in the authorized parampara as one’s worshipable deity and life and soul, there is no question of overcoming the duality of material life.
Srila Bhaktisiddhanta Sarasvati Thakura has made the following comments on this verse. “Control of the mind is a result of living a life of devotional service to the Lord. By the influence of fixed devotional service, the accepting and rejecting mind can stop its thirst for sensory enjoyment apart from Krsna. In transcendental Krsna consciousness there is no contradiction, pettiness or lack of ecstasy. In other words, it is not like a material object, which always proves temporary and constantly miserable. Having forgotten Krsna, the conditioned living entity is suffering the misdirection and perversion of his own so-called intelligence. The living entities are fragmental parts of the supreme shelter, Krsna, but have fallen from Krsna’s kingdom of spiritual pastimes. Because of forgetting the Supreme Lord, they become prone to sinful life and turn their attention to dangerous material objects, which fill them with constant fear. If one desires to subdue the mind, which is constantly engaged in the duality of mental concoction, one must take to the devotional service of Lord Krsna.”
Srimad Bhagavatam Canto 11, Chapter 02, Text 37
Srimad Bhagavatam Canto 11, Chapter 02, Text 39