Holy Orders is the means that Christ uses to provide the faithful with true shepherds after his own heart; this Sacrament imprints in the soul a character, a certain spiritual and indelible Sign, and is received only once, but in three degrees: deacon, priest, bishop. The Pope is both a bishop and the leader of all bishops; he is hte successor to Saint Peter. By ordination, a bishop becomes a true successor to the first Apostles. Priests are ordained to be assistants to the bishops, and to offer the faithful the Gospel and the Sacraments. Deacons assist both bishops and priests; they are appointed to serve the faithful in works of mercy and to preach the Gospel (cf. Acts 6). Ordained persons have a role in the Church that is not given to the laity. Consecrated persons (monks and nuns) are non-ordained members of the laity.