Occasionally at my church, a layperson will give the homily instead of the priest. It has been my understanding up until I read a question on this forum that it was okay in some circumstances for someone other than a priest to give the homily. Am I wrong?
The Congregation for Divine Worship states in Inaestimabile Donum # 3: “Accordingly the homily is to be given by the priest or the deacon.” The “Instruction on Certain Questions Regarding the Collaboration of the Non-Ordained Faithful in the Sacred Ministry of the Priest,” issued by the Congregation for the Clergy states more emphatically: “the homily, therefore, during the celebration of the Holy Eucharist, must be reserved to the sacred minister-priest or deacon—to the exclusion of the non-ordained faithful, even if these should have responsibilities as ‘pastoral assistants; or catechists in whatever type of community or group. This exclusion is not based on the preaching ability of sacred ministers nor their theological preparation, but on the function which is reserved to them in virtue of having received the Sacrament of Holy Orders. For the same reason, the bishop cannot validly dispense from the canonical form.” (ICP, Practical Provisions 3, Paragraph 1, 5)
There are situations where the laity my; be allowed to give a talk, but never in place of the homily at Mass.
Fr. Vincent Serpa, O.P.