BṚHADĀRAṆYAKA UPANISHAD · 6.4.27

अथैनं मात्रे प्रदाय स्तनं प्रयच्छति -- यस् ते स्तनः शशयो यो मयोभूर् यो रत्नधा वसुविद् यः सुदत्रः ।
येन विश्वा पुष्यसि वार्याणि सरस्वति तम् इह धातवे कर् इति ॥

athainaṃ mātre pradāya stanaṃ prayacchati -- yas te stanaḥ śaśayo yo mayobhūr yo ratnadhā vasuvid yaḥ sudatraḥ ।
yena viśvā puṣyasi vāryāṇi sarasvati tam iha dhātave kar iti ॥

Then he presents him to the mother and offers the breast, saying:-- 'Thy breast which is unfailing and refreshing, Wealth-bearer, treasure-finder, rich bestower, With which thou nourishest all things esteeméd-- Give it here, O Sarasvatî, to suck from. '

Robert Ernest Hume · The Thirteen Principal Upanishads (1921), Bṛhadāraṇyaka VI.4