Caitanya Caritamrta Madhya Lila 8.230

gopī-ānugatya vinā aiśvarya-jñāne
bhajileha nāhi pāya vrajendra-nandane

Unless one renders service unto the gopis he cannot attain the lotus feet of the son of Nanda Maharaja. If one is enamored by the knowledge of opulence of the Lord he also cannot attain the lotus feet of that sweet Lord even though he may be engaged in devotional service.

Who is the gopi referred in this verse? It is Radharani. The evidence is shown in pastime at Paithagaon. The gopis were searching for Krsna and Krsna manifested a four handed form as Narayana. The gopis ahead of Radha offered pranams and prayed that they can attain Krsna and then left. When Radharani came before Krsna, Krsna couldn’t maintain His four handed form and two arms entered into His body. Who saw Krsna’s two handed form? Only Radharani and the gopis following her. Therefore only serving under the guidance of Srimati Radharani one can get the service of vrajendra-nandan Sri Krsna.

[ Explanation to the verse given by Sri Srimad Bhakti Vijnana Bharati Maharaja ]
Written by Sankarshan Das