Śrīla Bhakti Siddhānta Saraswatī Ṭhākur explains the four qualities necessary for chanting the Name.
The following is a translation of the explanation of the third verse of the Śikṣāṣṭakam given by Śrīla Bhakti Siddhānta Saraswatī Ṭhākur in 1929 in a commentary called Vivṛti.
tṛṇād api sunīchena taror iva sahiṣṇunā
amāninā mānadena kīrtanīyaḥ sadā hariḥ
(Śrī Chaitanya-charitāmṛta: Ādi-līlā, 17.31)
[“The Lord’s Name is to be chanted always with more humility than a blade of grass, tolerance like that of a tree, honour for everyone, and without desire for honour from anyone.”]
As the soul is by nature a servant of Kṛṣṇa, the soul’s natural function, while residing in this world and spiritual world, is to perform constant glorification of the Lord (Hari-kīrtan). Amongst all means and ends of self-fulfilment and benefitting others, nothing compares with glorification of the Lord. Through glorification of the Lord, there is both altruism and all good fortune for oneself. The purpose of the verse tṛṇād api sunīchena is to explain the way by which one chants the Name without making offences to the Name (Nāmāparādh) or chanting a semblance of the Name (Nāmābhās).
Those who are not inclined towards Kṛṣṇa and are intoxicated by material enjoyment can never realise their insignificance. Enjoyers have no realisation of their natural insignificance and no natural tolerance. They are never able to give up material ego and material prestige, and are never willing to give prestige to other materialists. Material enjoyers are envious, but devotees immersed in the joy of serving the Name (Nām-bhajanānandī Vaiṣṇava) are humbler than a blade of grass, more tolerant than a tree, indifferent towards their own prestige, and eager to offer prestige to others. In this world, they alone are qualified and able to constantly chant the Lord’s Name.
The prestige indicative of honour that pure Vaiṣṇavas offer to their respective Āchāryas and Gurus, and to other Vaiṣṇavas, is produced by their natural propensity to honour others, and all the cordiality, respect, affection, and so forth that they show towards their followers to inspire them in service is simply an expression of such pure devotees’ natural pridelessness (amānitā). Pure devotees do not consider such honorary prestige to be material prestige, and, by tolerating the insinuations of the foolish, they reveal their tolerant nature.
Pure devotees engaged in chanting the Name consider themselves to be situated in a position lower than the grass that is trampled on by all living entities in the material world. Pure devotees never consider themselves to be Vaiṣṇavas or Gurus; they consider themselves disciples of the whole world and lower than everyone else. Knowing every atom and every infinitesimal soul to be an abode of Kṛṣṇa, they do not consider anything to be inferior to themselves.
Those who chant the Name do not request anyone for anything in this world. If others are inimical to them, they are never vengeful; rather, they pray for the welfare of their aggressors. Those who perform kīrtan never abandon the method they received from Śrī Gurudev and never, with the desire to preach a new conception, create a jingle of imaginary Names instead of chanting the mahāmantra of the Lord’s Name. When a Vaiṣṇava, under the guidance of Śrī Gurudev, writes books and performs kīrtan to preach about the chanting and glories of the Name, their humility is not checked. Deceitful expressions and gestures of meekness, however, made because of one’s lack of sincerity and deceitful motive of misleading the public, are not indications of humility.
While chanting the Name of Kṛṣṇa, the great devotees (mahābhāgavatas) see the world as favourable to the service of Kṛṣṇa and His devotees instead of seeing enjoyable moving and inert material forms. They do not, out of the tendency to enjoy, consider the world to be meant for their enjoyment. They do not create mantras, give up the chanting of the mahāmantra they received from Śrī Guru, or engage themselves in preaching new conceptions. Considering oneself a Guru of Vaiṣṇavas is an impediment to humility. In gist: the Lord’s Name cannot be chanted in the mouth of one who desires the position of a Vaiṣṇava or Guru but does not listen to the statements of Śrī Gaurasundar in the Śikṣāṣṭaka and is forgetful of one’s true self out of greed for wealth and prestige for the purpose of sense gratification. By such kīrtan [by the so-called kīrtan performed by such a person], faithful disciples also will not attain the qualification to hear the Lord’s Name.