SB 7.9.8

śrī-prahrāda uvāca
brahmādayaḥ sura-gaṇā munayo ’tha siddhāḥ
 sattvaikatāna-gatayo vacasāṁ pravāhaiḥ
nārādhituṁ puru-guṇair adhunāpi pipruḥ
 kiṁ toṣṭum arhati sa me harir ugra-jāteḥ
Synonyms: 
śrī-prahrādaḥ uvāca — Prahlāda Mahārāja prayed; brahma-ādayaḥ — headed by Lord Brahmā; sura-gaṇāḥ — the inhabitants of the upper planetary systems; munayaḥ — the great saintly persons; atha — as well (like the four Kumāras and others); siddhāḥ — who have attained perfection or full knowledge; sattva — to spiritual existence; ekatāna-gatayaḥ — who have taken without diversion to any material activities; vacasām — of descriptions or words; pravāhaiḥ — by streams; na — not; ārādhitum — to satisfy; puru-guṇaiḥ — although fully qualified; adhunā — until now; api — even; pipruḥ — were able; kim — whether; toṣṭum — to become pleased; arhati — is able; saḥ — He (the Lord); me — my; hariḥ — the Supreme Personality of Godhead; ugra-jāteḥ — who am born in an asuric family.
Translation: 
Prahlāda Mahārāja prayed: How is it possible for me, who have been born in a family of asuras, to offer suitable prayers to satisfy the Supreme Personality of Godhead? Even until now, all the demigods, headed by Lord Brahmā, and all the saintly persons, could not satisfy the Lord by streams of excellent words, although such persons are very qualified, being in the mode of goodness. Then what is to be said of me? I am not at all qualified.
Purport: 

A Vaiṣṇava who is fully qualified to serve the Lord still thinks himself extremely low while offering prayers to the Lord. For example, Kṛṣṇadāsa Kavirāja Gosvāmī, the author of Caitanya-caritāmṛta, says:

jagāi mādhāi haite muñi se pāpiṣṭha
 purīṣera kīṭa haite muñi se laghiṣṭha

(Cc. Ādi 5.205)

Thus he considers himself unqualified, lower than the worms in stool, and more sinful than Jagāi and Mādhāi. A pure Vaiṣṇava actually thinks of himself in this way. Similarly, although Prahlāda Mahārāja was a pure, exalted Vaiṣṇava, he thought himself most unqualified to offer prayers to the Supreme Lord. Mahājano yena gataḥ sa panthāḥ. Every pure Vaiṣṇava should think like this. One should not be falsely proud of his Vaiṣṇava qualifications. Śrī Caitanya Mahāprabhu has therefore instructed us:

tṛṇād api sunīcena
 taror api sahiṣṇunā
amāninā mānadena
 kīrtanīyaḥ sadā hariḥ

“One should chant the holy name of the Lord in a humble state of mind, thinking oneself lower than the straw in the street; one should be more tolerant than a tree, devoid of all sense of false prestige and should be ready to offer all respect to others. In such a state of mind one can chant the holy name of the Lord constantly.” Unless one is meek and humble, to make progress in spiritual life is very difficult.