CC Madhya 8.71
rāya kahe, “dāsya-prema — sarva-sādhya-sāra”
Hearing up to the point of spontaneous love, the Lord said, “This is all right, but if you know more, please tell Me.”
In reply, Rāmānanda Rāya said, “Spontaneous loving service in servitude — as exchanged by master and servant — is the highest perfection.
Spontaneous loving service to the Lord is called devotional service with an intimate attachment between the servitor and the served. This intimacy is called mamatā. Between the servitor and the served there is a feeling of oneness. This mamatā begins with dāsya-prema, service rendered to the master by the servant. Unless there is such a relationship, the loving affairs between the Lord and His devotee are not actually fixed. When the devotee feels “The Lord is my master” and renders service unto Him, Kṛṣṇa consciousness is awakened. This fixed consciousness is on a higher platform than simple cognizance of love of Godhead.