All liturgical celebrations should teach us something about our faith. Sacraments point us to God and gives us the grace to live out the Christian faith. Marriage is a sacrament and as such has a liturgy connected with it.
The Liturgy of the Word is an integral part of all sacramental celebrations. It consists of an Old Testament reading, “the writings of the prophets” which lay the foundation for our Christian faith, a psalm, “the memoirs of the apostles” which begin to put the Christian faith in practice and the Gospel of Jesus Christ, a homily that is an exhortation to accept this Word and put it into practice and general intercessions.
The Scripture readings, homily, intercessions and music should flow like a symphony. They should build on one another and put each other in context.
The Rite of Marriage reflects this. According to the Rite, there may be three readings. If three readings are used then the first reading is from the Old Testament and the Second Reading is from the New Testament and the third reading is always the Gospel. If just a New Testament reading is chosen there must also be a Gospel chosen.