The exemplary character of devotional service manifested by the devotees of Vrndavana is the purest type of devotion. It is enjoined in authoritative sastras that devotional service must be ahaituki and apratihata. This means that devotional service to Krsna cannot be checked by political or religious convention. The stage of devotional service is always transcendental. The gopis particularly showed pure devotional service toward Krsna, so much so that Krsna Himself remained indebted to them. Lord Caitanya thus said that the devotional service manifested by the gopis in Vrndavana excelled all other methods of approaching the Supreme Personality of Godhead.

From Srila Prabhupada’s Krsna Book, ch. 32: Krsna Returns to the Gopis