MuU 1.2.9
अविद्यायां बहुधा वर्तमाना वयं कृतार्था इत्यभिमन्यन्ति बालाः । यत् कर्मिणो न प्रवेदयन्ति रागात् तेनातुराः क्षीणलोकाश्च्यवन्ते
avidyāyāṃ bahudhā vartamānā vayaṃ kṛtārthā ityabhimanyanti bālāḥ | yat karmiṇo na pravedayanti rāgāt tenāturāḥ kṣīṇalokāścyavante
Sanskrit for this text is pending; the English follows the translator's numbering.
Children, when they have long lived in ignorance, consider themselves happy. Because those who depend on their good works are, owing to their passions, improvident, they fall and become miserable when their life (in the world which they had gained by their good works) is finished.
Translated by F. Max Müller