Bhagavad Gita 15.1
Lord Shri Krishna continued: This phenomenal creation, which is both ephemeral and eternal, is like a tree, with its seed above in the Highest and its ramifications below on this earth. The scriptures are its leaves, and he who understands this knows.
श्री भगवानुवाचऊर्ध्वमूलमधःशाखमश्वत्थं प्राहुरव्ययम्।छन्दांसि यस्य पर्णानि यस्तं वेद स वेदवित्॥śrī bhagavānuvācaūrdhvamūlamadhaḥśākhamaśvatthaṃ prāhuravyayam|chandāṃsi yasya parṇāni yastaṃ veda sa vedavit||
English translation (above): Shri Purohit Swami (1935), public domain. Sanskrit text via github.com/gita/gita (Unlicense).