I am not a brahmana, I am not a ksatriya, I am not a vaisya or a sudra. Nor am I a brahmacari, a householder, a vanaprastha or a sannyasi. I identify Myself only as the servant of the servant of the servant of the lotus feet of Lord Sri Krsna

Expressions researched:
"I am not a brāhmaṇa, I am not a kṣatriya, I am not a vaiśya or a śūdra. Nor am I a brahmacārī, a householder, a vānaprastha or a sannyāsī. I identify Myself only as the servant of the servant of the servant of the lotus feet of Lord Śrī Kṛṣṇa"

Sri Caitanya-caritamrta

CC Madhya-lila

“‘I am not a brāhmaṇa, I am not a kṣatriya, I am not a vaiśya or a śūdra. Nor am I a brahmacārī, a householder, a vānaprastha or a sannyāsī. I identify Myself only as the servant of the servant of the servant of the lotus feet of Lord Śrī Kṛṣṇa, the maintainer of the gopīs. He is like an ocean of nectar, and He is the cause of universal transcendental bliss. He is always existing with brilliance.’”

CC Madhya 13.80, Translation and Purport

“‘I am not a brāhmaṇa, I am not a kṣatriya, I am not a vaiśya or a śūdra. Nor am I a brahmacārī, a householder, a vānaprastha or a sannyāsī. I identify Myself only as the servant of the servant of the servant of the lotus feet of Lord Śrī Kṛṣṇa, the maintainer of the gopīs. He is like an ocean of nectar, and He is the cause of universal transcendental bliss. He is always existing with brilliance.’”

This is verse 74 from the Padyāvalī, an anthology of verses compiled by Śrīla Rūpa Gosvāmī.