Sri Aurobindo
Letters on Yoga
5. Planes and Parts of the Being
I do not understand. The Personal Divine does not mean the 
Avatar. What I said was that the scission between the two aspects of the Divine is a creation of the overmind which takes various aspects of the Divine and separates them into separate entities. Thus it divides Sat, Chit and Ananda, so that they become three separate aspects different from each other. In fact in the Reality there is no separateness, the three aspects are so fused into each other, so inseparably one that they are a single undivided reality. It is the same with the Personal and Impersonal, the Saguna and Nirguna, the Silent and the Active Brahman. In the Reality they are not contrasted and incompatible aspects; what we call Personality and what we call Impersonality are inseparably fused together into a single Truth. In fact “fused together” even is a wrong phrase, because there they were never separated so that they have to be fused. All the quarrels about either the Impersonal being the only true truth or the Personal being the only highest truth are mind-created quarrels derivative from this dividing aspect of the overmind. The overmind does not deny any in the aspects as the Mind does, it admits them all as aspects of the One Truth, but by separating them it originates the quarrel in the more ignorant and more limited and divided Mind, because the Mind, cannot see how two opposite things can exist together in one Truth, how the Divine can be nirguṇo guṇī; – having no experience of what is behind the two words it takes each in an absolute sense. The Impersonal is Existence, Consciousness, Bliss, not a Person, but a state. The Person is the Existent, the Conscious, the Blissful; consciousness, existence, bliss taken as separate things are only states of his being. But in fact the two (personal being and eternal state) are inseparable and are one reality.
Current publication:
Sri Aurobindo. Letters on Yoga // SABCL.- Volume 22. (≈ 28 vol. of CWSA).- Pondicherry: Sri Aurobindo Ashram, 1971.- 502 p.
Other publications:
1. 8421.
[Largest or earliest found passage: ]Sri Aurobindo. Letters on Himself and the Ashram // CWSA.- Volume 35. (≈ 26 vol. of SABCL).- Pondicherry: Sri Aurobindo Ashram, 2011.- 658 p.
2. 10026.
Sri Aurobindo. Letters on Yoga. I // CWSA.- Volume 28. (≈ 22 vol. of SABCL).- Pondicherry: Sri Aurobindo Ashram, 2012.- 590 p.
3. 23006.
Sri Aurobindo. Lights on Yoga [: Extracts from letters] / Reprint April 1977; First Edition: 1935.– Pondicherry: Sri Aurobindo Ashram, 1977.– 104 p.