The substrate from which rajas arises
'Tamahas tu rajah' (SB 1.2.24).
Concept
Tamas-guna
तमोगुण
Also known as तमस् · Tamas
Tamas-guna is prakriti's third mode: darkness, inertia, heedlessness and the propensity to ignorance. In the processed verses rajas arises from it (SB 1.2.24); with rajas it clouds the mind until hearing of the Lord washes it away (1.2.17-19).
Śrīmad Bhāgavata Mahāpurāṇa 1.2.19 — Sanskrit Wikisource (pinned oldid=110173)