Evolution of Life and Form: Four Lectures delivered at the Twenty-third Anniversary Meeting of the Theosophical Society at Adyar, Madras, 1898.

The Self in man, being in the image of God, is triple as the Self, the Divine, is triple. I need not stop to argue this. You know it from that great literature which lies at the foundation of all Hindu Philosophy. Whether you speak in abstract terms and say with the Upanishad that Brahman is threefold, whether you speak of Him as Sat-chit-ânanda, or whether, instead of using philosophical, abstract terms, you say He is manifest as Íshvara in the Trimûrti as Mahâdeva, Vishnu and Brahmâ, it matters not. You may take the concrete form or the abstract, the fundamental idea is the same: that the Divine Self in manifestation is triple, and therefore in every great religion God is spoken of as a Trinity. If this were not so, the relationship between God and man would remain for ever unintelligible, for man shows a triplicity as he evolves. The human reflection of that triple Divine Self is the triple Self in man.