SB 7.10.21
bhavanti purusa loke
mad-bhaktas tvam anuvratah
bhavan me khalu bhaktanam
sarvesam pratirupa-dhrk
Translation by His Divine Grace A. C. Bhaktivedanta Swami Srila Prabhupada:
Those who follow your example will naturally become My pure devotees. You are the best example of My devotee, and others should follow in your footsteps.
Purport by His Divine Grace A. C. Bhaktivedanta Swami Srila Prabhupada:
In this connection, Srila Madhvacarya quotes a verse from the Skanda Purana:
rte tu tattvikan devan
naradadims tathaiva ca
prahradad uttamah ko nu
visnu-bhaktau jagat-traye
There are many, many devotees of the Supreme Personality of Godhead, and they have been enumerated in Srimad-Bhagavatam (6.3.20) as follows:
svayambhur naradah sambhuh
kumarah kapilo manuh
prahlado janako bhismo
balir vaiyasakir vayam
Of the twelve authorized devotees — Lord Brahma, Narada, Lord Siva, Kapila, Manu and so on — Prahlada Maharaja is understood to be the best example.