A: The Universal Prayer or Prayers of the Faithful or General Intercessions are only obligatory on Sundays and Holy Days of Obligation.
Sacrosanctum Concilium (1963) called for the restoration of the Universal Prayer in the reform of the Sacred Liturgy: “Especially on Sundays and feasts of obligation there is to be restored, after the Gospel and the homily, ‘the common prayer’ or ‘the prayer of the faithful’” (53).
Shortly after this, in 1965, a question was put to the Congregation of Rites with regard to “Whether in Masses celebrated with the people, the prayer of the faithful is obligatory on ferial days?” The Congregation responded that, no, the obligation to pray the Universal Prayer “does not oblige” at daily Masses.
The current General Instruction of the Roman Missal (GIRM) stands in continuity with the Congregation when it states, “It is desirable [expedit] that there usually be such a form of prayer in Masses celebrated with the people” (69). The Latin word employed here, expedit, does not constitute a strict obligation, but a suggestion.
So, while the Universal Prayer is not obligatory, it may be used at daily Masses to great benefit. Indeed, the Universal Prayer caps the Liturgy of the Word in a way similar to the reception of Holy Communion at the end of the Liturgy of the Eucharist. For in the Universal Prayer, the baptized exercise the very priesthood of Christ by mediating “for holy Church, for the civil authorities, for those oppressed by various needs, for all mankind, and for the salvation of the entire world” (SC, 53).
—Answered by Jeremy Priest