150 In an earlier age, these canonical prayers were attended by many of the faithful. But this gradually ceased, and, as We have already said, their recitation at present is the duty only of the clergy and of religious. The laity have no obligation in this matter. Still, it is greatly to be desired that they participate in reciting or chanting vespers sung in their own parish on feast days. We earnestly exhort you, Venerable Brethren, to see that this pious practice is kept up, and that wherever it has ceased you restore it if possible. This, without doubt, will produce salutary results when vespers are conducted in a worthy and fitting manner and with such helps as foster the piety of the faithful. Let the public and private observance of the feasts of the Church, which are in a special way dedicated and consecrated to God, be kept inviolable; and especially the Lord's day which the Apostles, under the guidance of the Holy Ghost, substituted for the sabbath. Now, if the order was given to the Jews: "Six days shall you do work; in the seventh day is the sabbath, the rest holy to the Lord. Every one that shall do any work on this day, shall die;" how will these Christians not fear spiritual death who perform servile work on feast-days, and whose rest on these days is not devoted to religion and piety but given over to the allurements of the world? Sundays and holydays, then, must be made holy by divine worship, which gives homage to God and heavenly food to the soul. Although the Church only commands the faithful to abstain from servile work and attend Mass and does not make it obligatory to attend evening devotions, still she desires this and recommends it repeatedly. Moreover, the needs of each one demand it, seeing that all are bound to win the favor of God if they are to obtain His benefits. Our soul is filled with the greatest grief when We see how the Christian people of today profane the afternoon of feast days; public places of amusement and public games are frequented in great numbers while the churches are not as full as they should be. All should come to our churches and there be taught the truth of the Catholic faith, sing the praises of God, be enriched with benediction of the blessed sacrament given by the priest and be strengthened with help from heaven against the adversities of this life. Let all try to learn those prayers which are recited at vespers and fill their souls with their meaning. When deeply penetrated by these prayers, they will experience what St. Augustine said about himself: "How much did I weep during hymns and verses, greatly moved at the sweet singing of thy Church. Their sound would penetrate my ears and their truth melt my heart, sentiments of piety would well up, tears would flow and that was good for me."
Source: Mediator Dei (Vatican.va)