Religio / Traditio: Religio is that which “binds” (religat) man to Heaven and engages his whole being; as for the word “traditio”, it is related to a more outward and sometimes fragmentary reality, besides suggesting a retrospective outlook. At its birth a RELIGIOn “binds” men to Heaven from the moment of its first revelation, but it does not become a “tradition”, or admit more that one “tradition”, till two or three generations later. (GTUFS: LightAW, Religio Perennis)
Religio Perennis: The essential function of human intelligence is discernment between the Real and the illusory, or between the Permanent and the impermanent, and the essential function of the will is attachment to the Permanent or to the Real. This discernment and this attachment are the quintessence of all spirituality. Carried to their highest level or reduced to their purest substance they constitute, in every great spiritual patrimony of humanity, the underlying universality or what may be called the RELIGIO perennis. It is to this that the sages adhere, while basing themselves necessarily on divinely instituted elements. (GTUFS: EchPW, 84)
The RELIGIO perennis is fundamentally this, to paraphrase the well-known saying of St. Irenaeus: the Real entered into the illusory so that the illusory might be able to return into the Real. It is this mystery, together with the metaphysical discernment and contemplative concentration that are its complement, which alone is important in an absolute sense from the point of view of gnosis. For the gnostic (in the etymological and rightful sense of that word) there is in the last analysis no other RELIGIOn. It is what Ibn Arabi called the “RELIGIOn of love”, putting the accent on the element of “realization”.
The two-fold definition of the RELIGIO perennis, discernment between the Real and the illusory, and a unifying and permanent concentration on the Real – implies in addition the criteria of intrinsic orthodoxy for every RELIGIOn and all spirituality. In order to be orthodox a RELIGIOn must possess a mythological or doctrinal symbolism establishing the essential distinction in question, and must offer a way that secures both the perfection of concentration and also its continuity. (GTUFS: LightAW, Religio Perennis)
Religio perennis – the primordial, universal and underlying RELIGIOn. This is what in the language of the Koran is designated by the term fitrah: the primordial norm, the profound nature of things. (GTUFS: ChristIslam, Alternations in Semitic Monotheism)