Bhagavad Gītā Chapter One verse 1

dhṛtarāṣṭra uvāca |
dharmakṣetre kurukṣetre samavetā yuyutsavaḥ |
māmakāḥ pāṇḍavāś cāiva kim akurvata saṃjaya ‖

dharma - essential qualities, according to the nature of anything; highest duty; customary observance or prescribed conductkśetra - the field

Commentaries and Reflections

Commentary by Paul Harvey:

“The first Śloka sets the saga on the field of Dharma.
Dharma is how we respond, whatever the situation,
presuming we can sustain our view within the present.
Karma is how we respond, having lost sight of our view,
because it’s become obscured by  the force of our memories.
Then Karma is the force now driving us through our memories.
So, Arjuna’s Dharma becomes obscured because of his Karma.”