192
Śrīmad-Bhāgavatam
[Canto 7, Ch. 9]
śrī-prahrāda uvāca 
  brahmādayaḥ sura-gaṇā munayo 'tha siddhāḥ 
  sattvaikatāna-gatayo vacasām pravāhaiḥ 
  nārādhitum puru-guṇair adhunāpi pipruḥ 
  kim toṣtum arhati sa me harir ugra-jāteḥ
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; toṣtum—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 pāpiṣtha 
  purīṣera kīta haite muñi se laghiṣtha 
  (Cc.  Adi  5.205)