Yaozdata Benveniste (1969 II: 179 ff.) has clarified the dual nature of the Indo-Europeans’ idea of sacrality as evidenced by their vocabulary: that which is “charged with divine power” is “positively sacred” (Av. spenta-, Germanic *hailaz, Lat. Sanctus, Gr. Hieròs); that which “contact is forbidden for man” (Av. yaozdata-, Germanic *wihaz, Lat. Sacer, Gr. Hàgios) is “negatively sacred”. A corresponding duality is found in the terms for religious observance, expressed on the one hand by verbs denoting either “to cause to grow, to strengthen” or one of the sacrifical operations, and on the other by those denoting religious attitude: the fear of offending a god, even involuntarly, but at the same time confidence in and even familiarity with the gods, especially in the case of some of them. In Vedic India the bonds of Varuna/Oath are held in awe, but Indra is treated as a “comrade” (yùj-). Indo-European religion contains strict prohibitions, but is a religion of freemen (Neckel 1920: 134; Höfler 1971: 371 ff.) http://www.centrostudilaruna.it/haudryreligion.html