The Priesthood of All Believers is a theological concept that asserts that all Christians have direct access to God without the need for a human intermediary, such as a priest. This idea was central to Martin Luther's teachings during the Protestant Reformation, as it challenged the Catholic Church's hierarchical structure and emphasized individual faith and personal relationship with God. By promoting this doctrine, Luther aimed to democratize religion, empowering believers to interpret scriptures for themselves and participate actively in their faith.