§1. In leading their lives, clerics are bound in a special way to pursue holiness since, having been consecrated to God by a new title in the reception of orders, they are dispensers of the mysteries of God in the service of His people.
§2. In order to be able to pursue this perfection: 1/ they are first of all to fulfill faithfully and tirelessly the duties of the pastoral ministry; 2/ they are to nourish their spiritual life from the two-fold table of sacred scripture and the Eucharist; therefore, priests are earnestly invited to offer the eucharistic sacrifice daily and deacons to participate in its offering daily; 3/ priests and deacons aspiring to the presbyterate are obliged to carry out the liturgy of the hours daily according to the proper and approved liturgical books; permanent deacons, however, are to carry out the same to the extent defined by the conference of bishops; 4/ they are equally bound to make time for spiritual retreats according to the prescripts of particular law; 5/ they are urged to engage in mental prayer regularly, to approach the sacrament of penance frequently, to honor the Virgin Mother of God with particular veneration, and to use other common and particular means of sanctification.
Source: Code of Canon Law (Vatican.va)