One who identifies his self as the inert body composed of mucus, bile, and air, who assumes his wife and family are permanently his own, who thinks an earthen image or the land of his birth is worshipable, or sees a place of pilgrimage as merely the water there, but who never identifies with, feels kinship with, worships, or even visits those who are wise in spiritual truth such a person is no better than a cow or an ass.
Lord Sri Krsna
By uttering the single name of Krsna just once, one attains the same benefit as that gained by reciting Lord Visnu's thousand names three times.
By worshiping the devotees of the Lord all one's desires will be fulfilled.
Mundaka Upanisad (3.1.10)
He is a miserly man who does not solve the problems of life as a human being and who thus quits this world like the cats and dogs, without understanding the science of self-realization.
Brhad-aranyaka Upanisad (3.8.10)
When the devotees of Lord Krsna dance, their steps crush the inauspiciousness of the earth, their glances destroy the inauspiciousness of the ten directions, and their raised arms push away the inauspiciousness in the demigods' planets.
Padma Purana and
One who performs worship of Lord Krsna but fails to worship His devotees should be understood to be not a devotee of the Lord but simply a victim of false pride.
Anyone who prays to Me and takes shelter from Me becomes My ward, and I protect him always from all sorts of calamities.
(Krsna's half-man, half-lion incarnation)
One cannot challenge the authority of the Supreme and know Him at the same time. He reserves the right of not being exposed to such a challenging spirit of an insignificant spark of the whole, a spark subjected to the control of the illusory energy.
His Divine Grace A.C. Bhaktivedanta
Srimad-Bhagavatam 1.2.21, Purport