The science of God analyzes the constitutional position of God and His diverse energies. Material nature is called prakṛti, or the energy of the Lord in His different puruṣa incarnations (expansions) as described in the Sātvata-tantra:
viṣṇos tu trīṇi rūpāṇi
puruṣākhyāny atho viduḥ
ekaṁ tu mahataḥ sraṣṭṛ
dvitīyaṁ tv aṇḍa-saṁsthitam
tṛtīyaṁ sarva-bhūta-sthaṁ
tāni jñātvā vimucyate
"For material creation, Lord Kṛṣṇa's plenary expansion assumes three Viṣṇus. The first one, Mahā-Viṣṇu, creates the total material energy, known as the mahat-tattva. The second, Garbhodakaśāyī Viṣṇu, enters into all the universes to create diversities in each of them. The third, Kṣīrodakaśāyī Viṣṇu, is diffused as the all-pervading Supersoul in all the universes and is known as Paramātmā. He is present even within the atoms. Anyone who knows these three Viṣṇus can be liberated from material entanglement."
(Bhagavad-Gita----7:4----purport).

The distinction between the living entities and the Lord is described in Śrīmad-Bhāgavatam (10.87.30) as follows:
aparimitā dhruvās tanu-bhṛto yadi sarva-gatās
tarhi na śāsyateti niyamo dhruva netarathā
ajani ca yan-mayaṁ tad avimucya niyantṛ bhavet
samam anujānatāṁ yad amataṁ mata-duṣṭatayā
"O Supreme Eternal! If the embodied living entities were eternal and all-pervading like You, then they would not be under Your control. But if the living entities are accepted as minute energies of Your Lordship, then they are at once subject to Your supreme control. Therefore real liberation entails surrender by the living entities to Your control, and that surrender will make them happy. In that constitutional position only can they be controllers. Therefore, men with limited knowledge who advocate the monistic theory that God and the living entities are equal in all respects are actually guided by a faulty and polluted opinion."
(Bhagavad-Gita----7:5----purport).

When one is fully purified, he realizes that his constitutional position is to be the eternal servant of God. So by association with pure devotees the inquisitive, the distressed, the seeker after material amelioration and the man in knowledge all become themselves pure.
(Bhagavad-Gita----7:17----purport).

The real constitutional position of the living entity is that of subordination to the Supreme Lord, who is pure knowledge. When one is deluded into separation from this pure knowledge, he becomes controlled by the illusory energy and cannot understand the Supreme Personality of Godhead.
(Bhagavad-Gita----7:27----purport).

The impersonalists do not know that forgetting their constitutional position as subordinate to the Supreme Lord is the greatest violation of God's law. Unless one is reinstated in his own constitutional position, it is not possible to understand the Supreme Personality or to be fully engaged in His transcendental loving service with determination.
(Bhagavad-Gita----7:28----purport).

The beginning of Kṛṣṇa consciousness is association of persons who are Kṛṣṇa conscious. Such association is spiritual and puts one directly in touch with the Supreme Lord, and, by His grace, one can understand Kṛṣṇa to be the Supreme Personality of Godhead. At the same time one can really understand the constitutional position of the living entity and how the living entity forgets Kṛṣṇa and becomes entangled in material activities.
(Bhagavad-Gita----7:30----purport).

Many subjects have been discussed in this chapter: the man in distress, the inquisitive man, the man in want of material necessities, knowledge of Brahman, knowledge of Paramātmā, liberation from birth, death and diseases, and worship of the Supreme Lord. However, he who is actually elevated in Kṛṣṇa consciousness does not care for the different processes. He simply directly engages himself in activities of Kṛṣṇa consciousness and thereby factually attains his constitutional position as an eternal servitor of Lord Kṛṣṇa.
(Bhagavad-Gita----7:30----purport).

The constitutional position of the living entity is different from the position he takes in the material world. In material consciousness his nature is to try to be the lord of matter, but in spiritual consciousness, Kṛṣṇa consciousness, his position is to serve the Supreme. When the living entity is in material consciousness, he has to take on various bodies in the material world. That is called karma, or varied creation by the force of material consciousness.
(Bhagavad-Gita----8:3----purport).

Actually any living entity, being part and parcel of Kṛṣṇa, is Kṛṣṇa. All the Vedas, therefore, aim only toward Kṛṣṇa. Whatever we want to know through the Vedas is but a progressive step toward understanding Kṛṣṇa. That subject matter which helps us purify our constitutional position is especially Kṛṣṇa.
(Bhagavad-Gita----9:17----purport).

As for protecting the body or abiding by the rules of society and state, certainly there are different activities, even for the devotees, in connection with the conditional life, and such activities are called conditional. Besides these, the living entity who is fully conscious of his spiritual nature and is engaged in Kṛṣṇa consciousness, or the devotional service of the Lord, has activities which are called transcendental. Such activities are performed in his constitutional position, and they are technically called devotional service.
(Bhagavad-Gita----9:30----purport).

One should not try to understand Kṛṣṇa as a human being. As stated previously, only a foolish person thinks Him to be a human being. This is again expressed here in a different way. A man who is not foolish, who is intelligent enough to understand the constitutional position of the Godhead, is always free from all sinful reactions.
(Bhagavad-Gita----10:3----purport).

The living entity, although Brahman by nature, has the desire to lord it over the material world, and due to this he falls down. In his constitutional position, a living entity is above the three modes of material nature, but association with material nature entangles him in the different modes of material nature—goodness, passion and ignorance.
(Bhagavad-Gita----14:27----purport).

There are many philosophical speculations about the constitutional position of the living entities and the Supreme Absolute Truth. Now in this verse the Supreme Personality of Godhead clearly explains that anyone who knows Lord Kṛṣṇa to be the Supreme Person is actually the knower of everything.
(Bhagavad-Gita----15:19----purport).

In the Śrīmad-Bhāgavatam, real devotional liberation is defined as the reinstatement of the living entity in his own identity, his own constitutional position. Theconstitutional position is already explained: every living entity is a part-and-parcel fragmental portion of the Supreme Lord. Therefore his constitutional position is to serve. After liberation, this service is never stopped. Actual liberation is getting free from misconceptions of life.
(Bhagavad-Gita----18:55----purport).

The constitutional position of a living entity, represented by Arjuna, is that he has to act according to the order of the Supreme Lord. He is meant for self-discipline. Śrī Caitanya Mahāprabhu says that the actual position of the living entity is that of eternal servant of the Supreme Lord. Forgetting this principle, the living entity becomes conditioned by material nature, but in serving the Supreme Lord he becomes the liberated servant of God. The living entity's constitutional position is to be a servitor; he has to serve either the illusory māyā or the Supreme Lord.
(Bhagavad-Gita----18:73----purport).