This document's purpose is to spell out the Church's understanding of the nature of revelation--the process whereby God communicates with human beings. It touches upon questions about Scripture, tradition, and the teaching authority of the Church. The major concern of the document is to proclaim a Catholic understanding of the Bible as the "word of God." Key elements include: Trinitarian structure, roles of apostles and bishops, and biblical reading in a historical context.

The central document of the Second Vatican Council, Lumen Gentium was promulgated by Pope Paul VI on November 21, 1964. This document is "the keystone" of the Councils whole Magisterium. It focuses on the whole Church as a communion of charity. With it, according to John Paul II, the Second Vatican Council wished to shed light on the Churchs reality: a wonderful but complex reality consisting of human and divine elements, visible and invisible.