This article presents an outline of a complex and dense “nexus” of meanings inherent to religious power and knowledge in the traditions of the Baniwa, an Arawak-speaking indigenous people of the Northwest Amazon. It demonstrates how Baniwa cosmology can be understood through the notion of intersubjectivity in which the deities and spirits, the religious specialists, and sacred instruments form an integrated whole. “Matter” and “Spirit” combine and separate in a myriad of ways in Baniwa cosmogony, cosmology, ontology, and eschatology. “Spirit” inhabits all forms, while ancestral “power and knowledge” are transmitted across generations through the living “owners” (or, “keepers”) and “masters” of religious traditions. The vehicles of meaning through which the universe came into being and is reproduced for all times, or can be destroyed by enemy outsiders are homologous in their material forms (bones, elongated tubes, flutes). These forms are infused with powerful, nonmaterial lifeforces (fluids, such as blood, saliva; breath) of the deities and hence of the origins of the cosmos. Ancestral knowledge and power together are critical to creating, reproducing, or destroying the universe; they are embodied and “emplaced” throughout the Baniwa sacred geography, as sources of life that are constantly circulating in fluid forms throughout the cosmos, renewed through ceremonial specialists and their sacred instruments. The notion of cosmic intersubjectivity allows us to understand how the whole universe is considered to be a living being, materialized through a variety of sacred instruments.