CC Madhya 19.185
kṛṣṇa-bhakti-rasa-madhye e pañca pradhāna
“The chief transcendental mellows experienced with the Supreme Personality of Godhead are five — śānta, dāsya, sakhya, vātsalya and madhura.
Śānta-bhakti-rasa is described in the Bhakti-rasāmṛta-sindhu (3.1.4-6) as follows:
sthāyī śānti-ratir dhīraiḥ śānta-bhakti-rasaḥ smṛtaḥ
kintv ātma-saukhyam aghanaṁ ghanaṁ tv īśa-mayaṁ sukham
dāsādi-van-mano-jñātva- līlāder na tathā matā
When śānta-rati (neutral attraction) exists continuously and is mixed with ecstatic emotion, and when the devotee relishes that neutral position, it is called śānta-bhakti-rasa. Śānta-bhakti-rasa devotees generally relish the impersonal feature of the Supreme Personality of Godhead. Since their taste of transcendental bliss is incomplete, it is called aghana, or not concentrated. A comparison is made between ordinary milk and concentrated milk. When the same devotee goes beyond the impersonal and tastes the service of the Supreme Personality of Godhead in His original form as sac-cid-ānanda-vigraha (His transcendental, blissful body, complete in knowledge and eternity), the taste is called concentrated (ghana) transcendental bliss. Sometimes the devotees in śānta-rasa relish transcendental bliss after meeting the Supreme Personality of Godhead, but this is not comparable to the transcendental bliss relished by the devotees situated in dāsya-rasa, the transcendental mellow in which one renders service to the Supreme Personality of Godhead.
Dāsya-rasa, or dāsya-bhakti-rasa, is described in the Bhakti-rasāmṛta-sindhu (3.2.3-4) as follows:
nītā cetasi bhaktānāṁ prīti-bhakti-raso mataḥ
bhidyate sambhrama-prīto gaurava-prīta ity api
When according to his desires the living entity develops love for the Supreme Personality of Godhead, this beginning stage of love is called dāsya-bhakti-rasa. Dāsya-bhakti-rasa is divided into two categories, called sambhrama-dāsya and gaurava-dāsya. In sambhrama-dāsya, the devotee renders respectful service to the Supreme Personality of Godhead, but in the more advanced gaurava-dāsya, the devotee feels he is receiving protection from the Lord.
Sakhya-bhakti-rasa is described as follows in the Bhakti-rasāmṛta sindhu (3.3.1):
nītaś citte satāṁ puṣṭiṁ rasaḥ preyān udīryate
“According to one’s original consciousness, ecstatic emotions may be exhibited as continuously existing in fraternity. When this stage of Kṛṣṇa consciousness is mature, it is called preyo-rasa or sakhya-bhakti-rasa.”
Vātsalya-bhakti-rasa is described in the Bhakti-rasāmṛta-sindhu (3.4.1) as follows:
eṣa vatsala-nāmātra prokto bhakti-raso budhaiḥ
“When eternally existing love of Godhead transforms into parental love and is mixed with corresponding emotions, that stage of spiritual existence is described by learned devotees as vātsalya-bhakti-rasa.”
Madhura-bhakti-rasa is described in the Bhakti-rasāmṛta-sindhu (3.5.1) as follows:
madhurākhyo bhaved bhakti- raso ’sau madhurā ratiḥ
“If in accordance with one’s own natural development in Kṛṣṇa consciousness one’s attraction leans toward conjugal love within the heart, that is called attachment in conjugal love, or madhura-rasa.”