The word moha is very important in this verse. Moha refers to that which is opposed to knowledge. Actually real knowledge is the understanding that every living being is eternally a servitor of the Lord, but instead of thinking oneself in that position, the living entity thinks that he is not a servant, that he is the master of this material world, for he wants to lord it over the material nature. That is his illusion. This illusion can be overcome by the mercy of the Lord or by the mercy of a pure devotee. When that illusion is over, one agrees to act in Kṛṣṇa consciousness.
(Bhagavad-Gita-----18:73-----purport).

Elevation to this stage of ecstasy can be possible in two ways. One way is by constant association with pure devotees. The other way is by the special mercy of Kṛṣṇa or by the mercy of a pure devotee of Kṛṣṇa. Elevation to the ecstatic stage of life is generally attained through association with pure devotees, while elevation to that stage by the special mercy of Kṛṣṇa or His devotee is very rare. The purport is that one should execute devotional service rigidly in the association of devotees so that there will be certainty in raising oneself to that ecstatic position.
(Nectar of Devotion).

Pious activities bring about material opulence, but one cannot acquire devotional service by any amount of material pious activity—not by giving charity, opening big hospitals and schools or working philanthropically. Devotional service can be attained only by the mercy of a pure devotee. Without a pure devotee’s mercy, one cannot even escape the bondage of material existence.
(Sri Caitanya Caritamrta-------2:22:51--------purport).

In the preliminary phase of spiritual life there are different kinds of austerities, penances and similar processes for attaining self-realization. However, even if an executor of these processes is without any material desire, he still cannot achieve devotional service. And aspiring by oneself alone to achieve devotional service is also not very hopeful, because Kṛṣṇa does not agree to award devotional service to merely anyone. Kṛṣṇa can easily offer a person material happiness or even liberation, but He does not agree very easily to award a person engagement in His devotional service. Devotional service can in fact be attained only through the mercy of a pure devotee. In the Caitanya-caritāmṛta (Madhya 19.151) it is said, "By the mercy of the spiritual master who is a pure devotee and by the mercy of Kṛṣṇa one can achieve the platform of devotional service. There is no other way."
(Nectar of Devotion).

Pure devotees of the Lord are more powerful than the waters of the sacred river Ganges. One can derive spiritual benefit out of prolonged use of the Ganges waters. But one can be sanctified at once by the mercy of a pure devotee of the Lord. In Bhagavad-gītā it is said that any person, regardless of birth as śūdra, woman, or merchant, can take shelter of the lotus feet of the Lord and by so doing can return to Godhead. To take shelter of the lotus feet of the Lord means to take shelter of the pure devotees. The pure devotees whose only business is serving are honored by the names Prabhupāda and Viṣṇupāda, which indicate such devotees to be representatives of the lotus feet of the Lord. Anyone, therefore, who takes shelter of the lotus feet of a pure devotee by accepting the pure devotee as his spiritual master can be at once purified.
(Srimad Bhagavatam-------1:1:15------purport).

Bhaṭṭācārya offered him his due respect and replied, "My dear Gopīnātha Ācārya, it is through your mercy that I have received the mercy of the Supreme Lord." The mercy of the Supreme Personality of Godhead can be obtained by the mercy of a pure devotee. Lord Caitanya's mercy was bestowed upon Bhaṭṭācārya because of Gopīnātha Ācārya's endeavor. "You are a great devotee of the Lord," Bhaṭṭācārya continued, "and I was simply blinded by my academic education. Yes, I have obtained the mercy of the Lord through your agency only." Lord Caitanya Himself was greatly pleased to hear Bhaṭṭācārya say that a man can obtain the mercy of the Lord through the agency of a devotee. He appreciated his words and embraced Bhaṭṭācārya, confirming his statement.
(Teachings of Lord Caitanya).

The pastimes of Śrī Caitanya Mahāprabhu are full of nectar, and the pastimes of Lord Kṛṣṇa are like camphor. When one mixes these, they taste very sweet. By the mercy of the pure devotees, whoever tastes them can understand the depths of that sweetness.
(Sri Caitanya Caritamrta-------2:25:277------translation).