Mbh 12.319.2c

I answer, Kah is Purusha.[1667] That which is endued with change is Prakriti. He that is not endued therewith is Purusha. Similarly, that which is called Avidya (the unknowable) is Prakriti; and that which is called Vidya is Purusha. Thou hast asked me about the Mobile and the Immobile. Listen to what my answer is. That which is mobile is Prakriti, which undergoing modification, constitutes the cause of Creation and Destruction. The Immobile is Purusha, for without himself undergoing modifications he assists at Creation and Destruction. (According to a different system of philosophy) that which is Vedya is Prakriti; while that which is Avedya is Purusha. Both Prakriti and Purusha are said to be unintelligent, stable, indestructible, unborn, and eternal, according to the conclusions arrived at by philosophers conversant with the topics included in the name of Adhyatma. In consequence of the indestructibility of Prakriti in the matter of Creation, Prakriti, which is unborn, is regarded as not subject to decay or destruction. Purusha, again, is indestructible and unchangeable, for change it has none. The attributes that reside in Prakriti are destructible, but not Prakriti herself. The learned, therefore, call Prakriti indestructible. Prakriti also, by undergoing modifications, operates as the cause of Creation. The created results appear and disappear, but not original Prakriti. Hence also is Prakriti called indestructible. Thus have I told thee conclusions of the Fourth Science based on the principles of ratiocinative inference and having Emancipation for its end. Having acquired by the science of ratiocinative inference and by waiting upon preceptors, the Rich, the Samans, and the Yajushes, all the obligatory practices should be observed and all the Vedas studied with reverence, O Viswavasu!