Pseudo-Dionysius on participation

Wherefore all things share in that Providence which streams forth from the superessential Deific Source of all; for they would not be unless they had come into existence through participation in the Essential Principle of all things. —Pseudo-Dionysius, The Celestial Hierarchy (emphasis mine)

A loaded quotation with Pseudo-Dionysius at perhaps his most (Neo)Platonic: captures the idea of participation, the distinction between what we might call The One and everything else, and admits of it as a principle, indeed THE principle that delimits Being (essence) itself.

Overall the writings attributed to him are comparatively short but so crammed with nuance that they make for slow going (and much fruitful distillation).