The Lord is the purest, and thus anyone who wants to serve the Supreme Lord must also be pure. Unless a person is pure, he can neither understand what the Personality of Godhead is nor engage in His service in love

Expressions researched:
"The Lord is the purest, and thus anyone who wants to serve the Supreme Lord must also be pure. Unless a person is pure, he can neither understand what the Personality of Godhead is nor engage in His service in love"

Narada-bhakti-sutra (sutras 1 to 8 only)

The Lord is the purest, and thus anyone who wants to serve the Supreme Lord must also be pure. Unless a person is pure, he can neither understand what the Personality of Godhead is nor engage in His service in love, for devotional service, as stated before, begins from the point of self-realization, when all misgivings of materialistic life are vanquished.

Narada Bhakti Sutra 2, Purport:

The next stage is called anartha-nivṛtti, in which all the misgivings of material life are vanquished. A person gradually reaches this stage by regularly performing the primary principles of devotional service under the guidance of the spiritual master. There are many bad habits we acquire in the association of material contamination, chief of which are illicit sexual relationships, eating animal food, indulging in intoxication, and gambling. The first thing the expert spiritual master does when he engages his disciple in regulated devotional service is to instruct him to abstain from these four principles of sinful life.

Since God is supremely pure, one cannot rise to the highest perfectional stage of love of God without being purified. In the Bhagavad-gītā (10.12), when Arjuna accepted Kṛṣṇa as the Supreme Lord, he said, pavitraṁ paramaṁ bhavān: "You are the purest of the pure." The Lord is the purest, and thus anyone who wants to serve the Supreme Lord must also be pure. Unless a person is pure, he can neither understand what the Personality of Godhead is nor engage in His service in love, for devotional service, as stated before, begins from the point of self-realization, when all misgivings of materialistic life are vanquished.

After following the regulative principles and purifying the material senses, one attains the stage of niṣṭhā, firm faith in the Lord. When a person has attained this stage, no one can deviate him from the conception of the Supreme Personality of Godhead. No one can persuade him that God is impersonal, without a form, or that any form created by imagination can be accepted as God. Those who espouse these more or less nonsensical conceptions of the Supreme Lord cannot dissuade him from firm faith in the Supreme Personality of Godhead, Kṛṣṇa.

In the Bhagavad-gītā Lord Kṛṣṇa stresses in many verses that He is the Supreme Personality of Godhead. But despite Lord Kṛṣṇa's stressing this point, many so-called scholars and commentators still deny the personal conception of the Lord. One famous scholar wrote in his commentary on the Bhagavad-gītā that one does not have to surrender to Lord Kṛṣṇa or even accept Him as the Supreme Personality of Godhead, but that one should rather surrender to "the Supreme within Kṛṣṇa." Such fools do not know what is within and what is without. They comment on the Bhagavad-gītā according to their own whims. Such persons cannot be elevated to the highest stage of love of Godhead. They may be scholarly, and they may be elevated in other departments of knowledge, but they are not even neophytes in the process of attaining the highest stage of perfection, love of Godhead. Niṣṭhā implies that one should accept the words of Bhagavad-gītā, the words of the Supreme Personality of Godhead, as they are, without any deviation or nonsensical commentary.