Once Lord Sri Krsna playfully manifested Himself as Narayana, with four victorious hands and a very beautiful form. When the gopis saw this exalted form, however, their ecstatic feelings were crippled - CC Madhya 9.150

Expressions researched:
"Once Lord Śrī Kṛṣṇa playfully manifested Himself as Nārāyaṇa, with four victorious hands and a very beautiful form. When the gopīs saw this exalted form, however, their ecstatic feelings were crippled"

Sri Caitanya-caritamrta

CC Madhya-lila

“‘Once Lord Śrī Kṛṣṇa playfully manifested Himself as Nārāyaṇa, with four victorious hands and a very beautiful form. When the gopīs saw this exalted form, however, their ecstatic feelings were crippled. A learned scholar, therefore, cannot understand the gopīs’ ecstatic feelings, which are firmly fixed upon the original form of Lord Kṛṣṇa as the son of Nanda Mahārāja. The wonderful feelings of the gopīs in ecstatic parama-rasa with Kṛṣṇa constitute the greatest mystery in spiritual life.’”.

CC Madhya 9.150, Translation and Purport

“‘Once Lord Śrī Kṛṣṇa playfully manifested Himself as Nārāyaṇa, with four victorious hands and a very beautiful form. When the gopīs saw this exalted form, however, their ecstatic feelings were crippled. A learned scholar, therefore, cannot understand the gopīs’ ecstatic feelings, which are firmly fixed upon the original form of Lord Kṛṣṇa as the son of Nanda Mahārāja. The wonderful feelings of the gopīs in ecstatic parama-rasa with Kṛṣṇa constitute the greatest mystery in spiritual life.’”

This is a verse spoken by Nārada Muni in the Lalita-mādhava-nāṭaka (6.14), a drama written by Śrīla Rūpa Gosvāmī.