Bhagavad Gita Verse 8.3

श्रीभगवान्ने कहा– परम अक्षर ‘ब्रह्म’ है, अपना स्वरूप अर्थात् जीवात्मा ‘अध्यात्म’ नामसे कहा जाता है तथा भूतोंके भावको उत्पन्न करनेवाला जो त्याग है, वह ‘कर्म’ नामसे कहा गया है|

The Lord replied: Dear Arjuna, always remember that Brahma is the Supreme imperishable (everlasting); the Universal Soul. The Jeevatma or the soul within one’s body is known as Adhyatma.Karma is the offering made to the Gods that causes the creation or manifestation and also the preservation or sustenance of beings.