Leaders of Opus Dei describe the organization as a teaching entity whose main activity is to train Catholics to assume personal responsibility in sanctifying the secular world from within. This teaching is done by means of theory and practice.

Its lay people and priests organize seminars, workshops, retreats, and classes to help people put the Christian faith into practice in their daily lives. Spiritual Direction, one-on-one coaching with a more experienced lay person or priest, is considered the "paramount means" of training. Through these activities they provide religious instruction (doctrinal formation), coaching in spirituality for lay people (spiritual formation), character and moral education (human formation), lessons in sanctifying one's work (professional formation), and know-how in evangelizing one's family and workplace (apostolic formation).