CC Madhya 22.154
yā sā rāgānugocyate
virājantīm — shining intensely; abhivyaktām — fully expressed; vraja-vāsi-jana-ādiṣu — among the eternal inhabitants of Vṛndāvana; rāga-ātmikām — devotional service consisting of spontaneous love; anusṛtā — following; yā — which; sā — that; rāga-anugā — devotional service following in the wake of spontaneous love; ucyate — is said.
“ ‘Devotional service in spontaneous love is vividly expressed and manifested by the inhabitants of Vṛndāvana. Devotional service that accords with their devotional service is called rāgānugā bhakti, or devotional service following in the wake of spontaneous loving service.’
This verse is also found in the Bhakti-rasāmṛta-sindhu (1.2.270).