In plain words
From within Satya all things were created; in Satya the whole creation comes to rest; look where you will: what place is without the glory of Satya? This itself is pure sattva; see it!
You must know what pure sattva means. Many times I have created golden liṅgas and shown them to you. That itself is pure sattva. That itself pervades everywhere. (Bhagavān, creating a Hiraṇyagarbha liṅga and showing it) “This itself is pure sattva; see it!” Everything comes forth from this very pure sattva. There is no place anywhere without pure sattva. To confine such pure sattva to one form is a mistake. All these forms are nothing but pure sattva. This pure sattva is seen in each one as a subtle form, a form no bigger than an atom. In each age, for a cause of its own, this very pure sattva takes on an Avatāra of its own. In the Kṛta age this very pure sattva took the forms of Narasiṃha, Vāmana and the others; in the Tretā age it took the form of Śrī Rāmacandra; in the Dvāpara age it took the form of Śrī Kṛṣṇa. God is endowed with sixteen kalās. Only when those sixteen kalās are present is it the principle of fullness.
That is full, this is full; from the full the full comes forth; taking the full from the full, the full alone remains.