Bhagavatapurana 2.5.22

2.5.22

kālādguṇavyatikaraḥ pariṇāmaḥ svabhāvataḥ /
karmaṇo janma mahataḥ puruṣādhiṣṭhitādabhūt //

22. Presided over by Purusha, Kala becomes the cause of agitation (disturbance of the equilibrium) of the three gunas;

and nature (innate disposition) is the cause of modification, or change of form; and the activity of Mahat-tattva is the cause of Janma (the birth of anything).