Srimad Bhagvatam 7.14.39 states
dåñövä teñäà mitho nåëäm
tretädiñu harer arcä
kriyäyai kavibhiù kåtä
dåñövä—after practically seeing; teñäm—among the brähmaëas and Vaiñëavas; mithaù—mutually; nåëäm—of human society; avajïäna-ätmatäm—the mutually disrespectful behavior; nåpa—O King; tretä-ädiñu—beginning from Tretä-yuga; hareù—of the Supreme Personality of Godhead; arcä—the Deity worship (in the temple); kriyäyai—for the purpose of introducing the method of worship; kavibhiù—by learned persons; kåtä—has been done.
My dear King, when great sages and saintly persons saw mutually disrespectful dealings at the beginning of Tretä-yuga, Deity worship in the temple was introduced with all paraphernalia.
As it is said in Çrémad-Bhägavatam (12.3.52):
kåte yad dhyäyato viñëuà
tretäyäà yajato makhaiù
kalau tad dhari-kértanät
"Whatever result one obtained in Satya-yuga by meditating on Viñëu, in Tretä-yuga by performing sacrifices and in Dväpara-yuga by serving the Lord's lotus feet one can also obtain in Kali-yuga simply by chanting the Hare Kåñëa mahä-mantra." In Satya-yuga, every person was spiritually advanced, and there was no envy between great personalities. Gradually, however, because of material contamination with the advance of the ages, disrespectful dealings appeared even among brähmaëas and Vaiñëavas. Actually, an advanced Vaiñëava is to be respected more than Viñëu. As stated in the Padma Puräëa, ärädhanänäà sarveñäà viñëor ärädhanaà param: of all kinds of worship, worship of Lord Viñëu is the best. Tasmät parataraà devi tadéyänäà samarcanam: and recommended more than worship of Viñëu is worship of the Vaiñëava.
Formerly, all activities were performed in connection with Viñëu, but after Satya-yuga there were symptoms of disrespectful dealings among Vaiñëavas. Çréla Bhaktivinoda Öhäkura has said that a Vaiñëava is he who has helped others become Vaiñëavas. An example of one who has converted many others into Vaiñëavas is Närada Muni. A powerful Vaiñëava who has converted others into Vaiñëavas is to be worshiped, but because of material contamination, sometimes such an exalted Vaiñëava is disrespected by other, minor Vaiñëavas. When great saintly persons saw this contamination, they introduced worship of the Deity in the temple. This began in Tretä-yuga and was especially prominent in Dväpara-yuga (dväpare paricaryäyäà). But in Kali-yuga, worship of the Deity is being neglected. Therefore chanting of the Hare Kåñëa mantra is more powerful than Deity worship. Çré Caitanya Mahäprabhu set a practical example in that He did not establish any temples or Deities, but He profusely introduced the saìkértana movement. Therefore Kåñëa consciousness preachers should give more stress to the saìkértana movement, especially by distributing transcendental literature more and more. This helps the saìkértana movement. Whenever there is a possibility to worship the Deity, we may establish many centers, but generally we should give more stress to the distribution of transcendental literature, for this will be more effective in converting people to Kåñëa consciousness.
It is said in Çrémad-Bhägavatam (11.2.47):
arcäyäm eva haraye
püjäà yaù çraddhayehate
na tad-bhakteñu cänyeñu
sa bhaktaù präkåtaù småtaù
"A person who is very faithfully engaged in the worship of the Deity in the temple but does not know how to behave toward devotees or people in general is called a präkåta-bhakta, or kaniñöha-adhikäré." A präkåta devotee, or neophyte devotee, is still on the material platform. He certainly engages in worshiping the Deity, but he cannot appreciate the activities of a pure devotee. It has actually been seen that even an authorized devotee who is engaged in the service of the Lord by preaching the mission of Kåñëa consciousness is sometimes criticized by neophyte devotees. Such neophytes are described by Viçvanätha Cakravarté Öhäkura: sarva-präëi-sammänanäsamarthänäm avajïä spardhädimatäà tu bhagavat-pratimaiva pätram ity äha. For those who cannot properly appreciate the activities of authorized devotees, Deity worship is the only way for spiritual advancement. In the Caitanya-caritämåta (Antya 7.11) it is clearly said, kåñëa-çakti vinä nahe tära pravartana: without being authorized by Kåñëa, one cannot preach the holy name of the Lord throughout the entire world. Nevertheless, a devotee who does so is criticized by neophyte devotees, kaniñöha-adhikärés, who are on the lower stages of devotional service. For them, Deity worship is strongly recommended.