Garland of 108 Precious Gems
Ashtotthara Satha Nama Rathnamala
5. Om Sri Sai Sathpurushaaya Namah
The Universal Eternal Absolute can be cognized only as Sath, Chith, and Ananda. 'It is' -- 'It knows' -- 'It is Bliss'. It is all this, ever. Ekam eva advitheeyam; one only, without a second. That Ekam felt, 'Ekoham bahusyaam'; 'I am one, let Me become Many' and all this came about. Baba is He who willed so. He is the Sath. Purusha means : "Poornam anena sarvam" -- He by whom all this is filled. Purusha also means, the dweller in the Puram or Fort. The Fort is the body with five rings of walls (the Panchakosas) and the nine fates. 'Deho devalayah proktho, jeevo devah sanaathanah', the body is the Temple and He is the God installed therein : As Sath, Baba is all this; as Purusha, He is in our Puram or Body, in a special sense.
Sath Purusha also means 'a good person', any good person. Now, while Baba is in persons, He is more manifest, patent and potent in "good persons". A person is good because He has toughened his detachment; He has strengthened his impulse to serve others; He has broadened his vision; He has widened his sympathies. Baba is the real motivator in all Sath-purushas, in all good men. He is the One Sath Purusha, of whom the good men of the world are faint fractional images.
(From : Garland of 108 Precious Gems,
Ashtotthara Sathanama Rathnamala, by Prof N Kasturi)