1983 Code of Canon Law as it Pertains to Preaching (Hyperlinks will take you to the appendix of the Code of Canon Law on the Vatican Website)
Can. 762 Sacred ministers, among whose principal duties is the proclamation of the gospel of God to all, are to hold the function of preaching in esteem since the people of God are first brought together by the word of the living God, which it is certainly right to require from the mouth of priests.
Can. 763 Bishops have the right to preach the word of God everywhere, including in churches and oratories of religious institutes of pontifical right, unless the local bishop has expressly forbidden it in particular cases.
Can. 764 Without prejudice to the prescript of ⇒ can. 765, presbyters and deacons possess the faculty of preaching everywhere; this faculty is to be exercised with at least the presumed consent of the rector of the church, unless the competent ordinary has restricted or taken away the faculty or particular law requires express permission.
Can. 766 Lay persons can be permitted to preach in a church or oratory, if necessity requires it in certain circumstances or it seems advantageous in particular cases, according to the prescripts of the conference of bishops and without prejudice to ⇒ can. 767, §1.
Can. 767 §1. Among the forms of preaching, the homily, which is part of the liturgy itself and is reserved to a priest or deacon, is preeminent; in the homily the mysteries of faith and the norms of Christian life are to be explained from the sacred text during the course of the liturgical year.
§3. It is strongly recommended that if there is a sufficient congregation, a homily is to be given even at Masses celebrated during the week, especially during the time of Advent and Lent or on the occasion of some feast day or a sorrowful event.
§2. They are also to impart to the faithful the doctrine which the magisterium of the Church sets forth concerning the dignity and freedom of the human person, the unity and stability of the family and its duties, the obligations which people have from being joined together in society, and the ordering of temporal aVairs according to the plan established by God.
Can. 770 At certain times according to the prescripts of the diocesan bishop, pastors are to arrange for those types of preaching which are called spiritual exercises and sacred missions or for other forms of preaching adapted to needs.
Can. 771 §1. Pastors of souls, especially bishops and pastors, are to be concerned that the word of God is also proclaimed to those of the faithful who because of the condition of their life do not have suYcient common and ordinary pastoral care or lack it completely.