In plain words
Only a few have recognised the principle of the antaḥkaraṇa and taken man to be this causal body, whose form is vāsanās. Only one in a crore has truly recognised the truth that man is the great causal principle, whose form is the Ātma. Looking with the eye of Vijñāna, he who leaves behind these three covering bodies, casts them off, puts them away, and recognises the great causal principle of the Ātma: he alone is blessed. He alone is meritorious. So this gross body, this body of the five elements, is only a sheath and nothing more. It is like a fourth part of the body. The principle of this mind, all-knowing, all-powerful, all-pervading, is like no more than half the body, because it is joined with saṅkalpas. The principle of the antaḥkaraṇa, whose form is vāsanās, is like a third part. The Ātma principle, eternal and real, is joined with humanity in its fullness. It is this that the Puruṣa Sūkta speaks of: sahasra śīrṣā puruṣaḥ sahasrākṣa sahasrapāt. It has a thousand heads, it has a thousand eyes, it has a thousand feet. In short, it makes it plain that all feet, all heads and all eyes are reflections of the Paramātma.
Bhakti vaśaḥ puraḥ. That is, this body called the city is what yields to Bhakti. The principle of this mind that stands in the middle is the matter we must chiefly recognise. The mind is like a job at the middle grade. He can go up with a promotion. He can rise to a high grade. Through some faults he can also go down by Reversion, that is, to a lower grade. So whether the principle of this mind is to reach the higher level or slide down to the lower, our own saṅkalpas and vikalpas are the main causes. That is why they said, manayeva manuṣyāṇāṃ kāraṇaṃ bandha mokṣayoḥ. The mind has two kinds of principle. These are vikṣepa and laya.
Vikṣepa is what belongs to activity bound up with the outside. It goes with the path of pravṛtti. This vikṣepa lives only in outward sight, which is the cause of the world. In the outer world a mind joined with steadiness is nowhere to be seen. It stays restless all the time. This is what was called vikṣepa. What moves, what is restless, what is unsteady: that is vikṣepa. It belongs only to the gross world of Prakṛti. Laya, on the other hand, is what stays in a state of complete blankness. The state of blankness is what stays in the state of sleep. In the state of sleep the principle of the mind shows not the least stirring of saṅkalpa.