Lay preaching outside of Mass is permitted in certain circumstances, but it cannot be called a homily. Laity cannot give the homily during Mass, nor may they preach during the time reserved for the homily. (
source)
The
only allowance for lay homilists I have found is from the Sacred Congregation for the Clergy, in a letter of Cardinal J. Wright to Cardinal J. Dopfner (president of the German conference of bishops), on preaching by the laity, from November 20, 1973. This quote below is
DOL 344 nn. 2957-2958. (DOL =
Documents on the Liturgy.) The permission was granted only to Germany, for a period of four years, under certain circumstances:1. In places lacking a priest or deacon, bishops are to choose layperson who will be
empowered to give a homily during the celebration of the word of God so that on Sundays and holydays of obligation the faithful may receive help to sanctify the day.
- a. During a Mass the celebrant normally gives the sermon.
b. But a celebrant may be physically or morally prevented from fulfilling this function, no other priest or deacon may be available, and thus the faithful may be deprived of the spiritual help coming from the word of God.
In such a case of compelling or reasonable need, bishops have the power to grant to laypersons the faculty to preach even during a Mass.
c. Bishops are empowered to grant the same faculty when on a particular occasion (for example, celebrations on behalf of the Christian family, to promote works of charity or foreign missions, or other celebrations at the discretion of the bishops) laypersons who have special qualifications and whose words are likely to be especially effective.
Other documents from that time period make it clear that
laypeople cannot give homilies during Mass:
- “In places without a priest and where none is available for celebration of Mass on Sundays and holydays of obligation, a sacred celebration of the word of God with a deacon or even a properly appointed layperson presiding, shall be arranged, at the discretion of the local Ordinary. … If the one presiding is a deacon, he shall give a homily; a nondeacon shall read a homily chosen by the bishop or the pastor.” (Sacred Congregation of Rites, Instruction Inter Oecumenici, n. 37, September 26, 1964 DOL 23 n. 329 )
- “The priest, therefore, is the homilist.]” (Sacred Congregation for Divine Worship, Instruction Liturgicae Instaurationes n. 2a, September 5, 1970 DOL 52 n. 513 )
- Query: “[May] those also who are neither priests nor deacons, both men and women, but take part in the liturgy, … give the homily?” Reply: “No.” (Pontifical Commission for the Interpretation of the Decrees of Vatican Council II, Reply to a query on GIRM n. 42, January 11, 1971 DOL 215 n. 1768 )