In Bhagavad-gītā (18.61) it is said:

īśvaraḥ sarva-bhūtānāṁ hṛd-deśe ’rjuna tiṣṭhati bhrāmayan sarva-bhūtāni yantrārūḍhāni māyayā

“The Supreme Lord is situated in everyone’s heart, O Arjuna, and is directing the wanderings of all living entities, who are seated as on a machine, made of the material energy.” The living entity, who is part and parcel of the Supreme Personality of Godhead, exists on the mercy of the Lord, who is always with him in any form of body. The living entity desires a particular type of material enjoyment, and thus the Lord supplies him with a body, which is like a machine. Just to keep him alive in that body, the Lord remains with him as the puruṣa (Kṣīrodakaśāyī Viṣṇu). This is also confirmed in Brahma-saṁhitā (5.35) :

eko ’py asau racayituṁ jagad-aṇḍa-koṭiṁ yac-chaktir asti jagad-aṇḍa-cayā yad-antaḥ aṇḍāntara-stha-paramāṇu-cayāntara-sthaṁ govindam ādi-puruṣaṁ tam ahaṁ bhajāmi

“I worship the Personality of Godhead, Govinda, who enters the existence of every universe and every atom by one of His plenary portions and thus manifests His infinite energy throughout the material creation.” The living entity, being part and parcel of the Lord, is known as jīva. The Supreme Lord puruṣa remains with the jīva to enable him to enjoy material facilities.