If I, Lord Brahma, and your elder brothers, the great saints and sages, cannot understand the limits of the Supreme Personality of Godhead, who is full of various energies, who else can understand them

Expressions researched:
"If I, Lord Brahmā, and your elder brothers, the great saints and sages, cannot understand the limits of the Supreme Personality of Godhead, who is full of various energies, who else can understand them"

Sri Caitanya-caritamrta

CC Madhya-lila

If I, Lord Brahmā, and your elder brothers, the great saints and sages, cannot understand the limits of the Supreme Personality of Godhead, who is full of various energies, who else can understand them? Although constantly chanting about His transcendental qualities, the thousand-hooded Lord Śeṣa has not yet reached the end of the Lord’s activities.

CC Madhya 21.13, Translation and Purport

If I, Lord Brahmā, and your elder brothers, the great saints and sages, cannot understand the limits of the Supreme Personality of Godhead, who is full of various energies, who else can understand them? Although constantly chanting about His transcendental qualities, the thousand-hooded Lord Śeṣa has not yet reached the end of the Lord’s activities.

This verse, spoken to Nārada Muni by Lord Brahmā, is also from Śrīmad-Bhāgavatam (SB 2.7.41).