Bhagavad Gita 15.11

The saints, with great effort, find Him within themselves; however, the unintelligent, despite their efforts, cannot control their minds.

यतन्तो योगिनश्चैनं पश्यन्त्यात्मन्यवस्थितम्।यतन्तोऽप्यकृतात्मानो नैनं पश्यन्त्यचेतसः॥

yatanto yoginaścainaṃ paśyantyātmanyavasthitam|yatanto'pyakṛtātmāno nainaṃ paśyantyacetasaḥ||

English translation (above): Shri Purohit Swami (1935), public domain. Sanskrit text via github.com/gita/gita (Unlicense).