Verse
द्वाविमौ पुरुषौ लोके क्षरश्चाक्षर एव च ।क्षरः सर्वाणि भूतानि कूटस्थोऽक्षर उच्यते ॥
There are two Purushas (spiritual beings) in this world, the immutable (and impersonal) and the mutable (and personal); the mutable is all these existences, the Kutastha (the high-seated consciousness of the Brahmic status) is called the immutable.
Gītā 15·16