Bhishma said 'All immobile and mobile beings, divided into four classes, have been described to be of unmanifest birth and unmanifest death. Existing only in the unmanifest Soul, the Mind is said to possess the attributes of the unmanifest.
गुरुरुवाच चतुर्विधानि भूतानि स्थावराणि चराणि च। अव्यक्तप्रभवान्याहुरव्यक्तनिधनानि च। अव्यक्तलक्षणं विद्यादव्यक्तात्मात्मकं मनः॥