Devotional service of the Lord that ignores the authorized Vedic literatures like the Upanisads, Puranas, and Narada-pancaratra is simply an unnecessary disturbance in society.

-Srila Rupa Gosvami
Bhakti-rasamrta-sindhu 1.2.101

May there be good fortune throughout the universe, and may all envious persons be pacified. May all living entities become calm by practicing bhakti-yoga, for by accepting devotional service they will think of each other's welfare. Therefore let us all engage in the service of the supreme transcendence, Lord Sri Krsna, and always remain absorbed in thought of Him.

-Sri Prahlada Maharaja
Srimad-Bhagavatam 5.18.9

As a lamp in a windless place does not waver, so the transcendentalist, whose mind is controlled, remains always steady in his meditation on the transcendent self.

-Lord Sri Krsna
Bhagavad-gita 6.19

As a mass of clouds does not know the powerful influence of the wind, a person engaged in material consciousness does not know the powerful strength of the time factor, by which he is being carried.

-Lord Kapiladeva
Srimad-Bhagavatam 3.30.1

Spiritual rasa [taste], which is relished even in the liberated stage, can be experienced in the literature of the Srimad-Bhagavatam due to its being the ripened fruit of all Vedic knowledge. By submissively hearing this transcendental literature, one can attain the full pleasure of his heart's desire.

-His Divine Grace A.C. Bhaktivedanta Swami Prabhupada
Srimad-Bhagavatam 1.1.3, purport

A materialistic person, thinking himself to be very advanced in intelligence, continually acts for economic development. But again and again, as enunciated in the Vedas, he is frustrated by material activities, either in this life or in the next. Indeed, the results one obtains are inevitably the opposite of those one desires.

-Sri Narada Muni
Srimad-Bhagavatam 7.7.4

One who has not listened to the messages about the prowess and marvelous acts of the Personality of Godhead and has not sung or chanted loudly the worthy songs about the Lord is to be considered to possess earholes like the holes of snakes and a tongue like the tongue of a frog.

-Sri Saunaka Rsi
Srimad-Bhagavatam 2.3.20