Samkhya Karika 57

वत्सविवृद्धिनिमित्तं क्षीरस्य यथा प्रवृत्तिरज्ञस्य ।
पुरुषविमोक्षनिमित्तं तथा प्रवृत्तिः प्रधानस्य ॥ ५७ ॥

vatsavivṛddhinimittaṁ kṣīrasya yathā pravṛttirajñasya ।
puruṣavimokṣanimittaṁ tathā pravṛttiḥ pradhānasya ॥ 57 ॥

Vatsa=calf; vivṛddhi=growth, nourishment; nimittaṁ=for the sake of; kṣīrasya=of the milk; yathā=just as; pravṛttiḥ=flow, action; ajñasya=insentient; puruṣa=Purusha; vimokṣa=liberation; nimittaṁ=for the sake of; tathā=in the same manner; pravṛttiḥ=action; pradhānasya=of mūla prakriti

Just as the production and flow of milk which is unintelligent, is for the nourishment of the calf, in the same manner, the action of Pradhana (Prakriti) is for the liberation of Purusha.