"In Śrīmad-Bhāgavatam, Mahādeva Śaṅkara, the god of gods, has been called the foremost Vaiṣṇava. He and Bhagavatī Pārvatī are always absorbed in meditation on Kṛṣṇa’s eternal eightfold daily pastimes (aṣṭa-kālīya līlā). Once, during Śrī Kṛṣṇa’s manifest pastimes, Śaṅkara desired to take darśana of Kṛṣṇa’s captivating rāsa-līlā with his own eyes. Being eager to do so, he came directly to Vṛndāvana from Kailāśa. At the gate outside Vṛndāvana, some attendant gopīs stopped him, because no male except for Śrī Kṛṣṇa can enter the rāsa. But since when has Śaṅkara easily agreed to anything? He asked the attendant gopīs how he might be admitted, and they told him to satisfy Bhagavatī Yogamāyā Paurṇamāsī (Pūrṇimā) with his worship. Śaṅkara followed their advice and after arduous worship he received darśana of Yogamāyā. Knowing the desire of Śaṅkara, Pūrṇimā took his hands and dipped him in the nearby Brahma-kuṇḍa. When he came out of the pond, he had been transformed into an extremely beautiful young gopī. Pūrṇimā seated Śaṅkara, now a gopī, inside a kuñja north-east of the rāsa-sthalī. She told him to behold the rāsa-līlā from there, and then she disappeared. After a short while, the rāsa-līlā began. The gopīs thought, “Today, for some reason or other, we are not feeling any happiness in singing and dancing.” They understood that some outsider had entered the arena, and they began to search for that person. In their search they came to this place‚ where they saw a new, unknown gopī sitting in a kuñja. They caught that new gopī and began to question her, “What is your name? What is the name of your village? Who is your husband? Who is your father-in-law?” But the new gopī was unable to answer any of their questions. Instead, she could only cry. Yogamāyā had neither arranged her birth from the womb of a gopī, nor given her any name. The new gopī was not married to any gopa either, so what answers could she give? When the gopīs received no answer, they began to slap her cheeks till they became swollen. Seeing Mahādeva’s misery, Pūrṇimā’s heart melted. She went there and explained that this gopī was an object of her mercy. She requested the gopīs and Kṛṣṇa to be merciful to her. Śrī Kṛṣṇa, knowing the internal desire of Pūrṇimā, gave Śaṅkara the name Gopīśvara and granted him the boon that a sādhaka would be unable to enter Vṛndāvana, and especially into Kṛṣṇa’s sweet pastimes there, without first receiving his mercy. The Gosvāmī literatures also describe that at the time of Kṛṣṇa’s manifest pastimes, the gopīs worshipped Gopīśvara Mahādeva with the desire to obtain service to Kṛṣṇa. For instance, Raghunātha dāsa Gosvāmī’s Śrī Vraja-vilāsa-stava (verse 87) states:

mudā gopendrasyātmaja-bhuja-pariṣvaṅga-nidhaye sphurada-gopī-vṛndairyamaiha bhagavantaṁ praṇayibhiḥ bhajadbhisa tair bhaktyā svama bhilaṣitaṁ prāptuma cirād yamī-tīre gopīśvaramanudinaṁ taṁ kila bhaje

“To obtain the jewel of being embraced by the arms of Vrajendra-nandana Śyāmasundara, the gopīs, who possess firm, loving, intimate attachment for Śrī Kṛṣṇa, joyfully worshipped Sadāśiva with great devotion and had all their internal desires fulfilled without delay. Daily I worship that Gopīśvara Mahādeva who resides on the bank of the Yamunā.”

The praṇāma-mantra (from Śrī Viśvanātha Cakravartī Ṭhākura’s Saṅkalpa-kalpa-druma, text 103) for Gopīśvara Mahādeva clearly indicates that Gopīśvara Mahādeva is the bestower of unadulterated kṛṣṇa-prema:

vṛndāvanāvani-pate! jaya soma! soma-maule sanaka-sanandana-sanātana-naradeḍya gopīśvara! vraja-vilāsī-yugāṅghri-padme prema prayaccha nirupādhi namo namste

“O gatekeeper of Vṛndāvana, O Soma, all glories to you. O you whose forehead is decorated with the moon, and who is worshipful for the sages headed by Sanaka, Sanandana, Sanātana and Nārada. O Gopīśvara, desiring that you bestow upon me prema for the lotus feet of Śrī Rādhā-Mādhava, who perform joyous pastimes in Vraja-dhāma, I offer obeisances unto you time and again.”

Excerpt from the book 'Sri Vraja-mandal Parikrama' by Srila Bhaktivedanta Narayana Gosvami Maharaja