There are two entities in this universe, namely the Perishable and the Imperishable. All creatures are the Perishable, and the unconcerned One is the Imperishable.
द्वाविमौ पुरुषौ लोके क्षरश्चाक्षर एव च। क्षरः सर्वाणि भूतानि कूटस्थोऽक्षर उच्यते॥