Bhagwat Geeta, Class 185 – Chapter 14 Verses 10 to 19
When sattva guṇa is dominant jñānendryas will be more operational, whereas rājo guṇa is dominant, karmēndriyas will be more functional; whereas when tāmo guṇa is dominant, neither jñānendryas nor karmēndriyas will be operational. Tamo guna will suppress jñānendrya and make them dull. Tamo guna will also suppress karmēndriyas also and there will be no activities. […]