Let me offer my respectful obeisances unto the all-auspicious Lord Śrī Kṛṣṇa again and again because the great learned sages, the great performers of charity, the great workers of distinction, the great philosophers and mystics, the great chanters of the Vedic hymns and the great followers of Vedic principles cannot achieve any fruitful result without dedication of such great qualities to the service of the Lord.
Srimad Bhagavata Purana
श्रीमद्भागवतमहापुराणम्
मूल श्लोकः
तपस्विनो दानपरा यशस्विनो मनस्विनो मन्त्रविदः सुमङ्गलाः । क्षेमं न विन्दन्ति विना यदर्पणं तस्मै सुभद्रश्रवसे नमो नमः
tapasvino dānaparā yaśasvino manasvino mantravidaḥ sumaṅgalāḥ | kṣemaṃ na vindanti vinā yadarpaṇaṃ tasmai subhadraśravase namo namaḥ
SB 2.4.17