The Lord dwells in the heart of all beings, Arjuna, and by his power of illusion he makes all beings go round, as if they were mounted on a machine.
Explanation
Krishna has just told Arjuna that his own nature will drive him to fight even if he refuses out of delusion. Here he says the Lord (Īśvara) abides in every heart and moves beings by his power of illusion (māyā), like riders on a machine. Advaita readers tend to see Īśvara as the inner Self working through māyā. Theistic traditions tend to see a personal God guiding beings according to their own karma.