The praying of the Collect marks the end of the Introductory Rites and we enter the Liturgy of the Word.

The Mass itself comprises of two liturgies: the Liturgy of the Word and the Liturgy of the Eucharist.  In the Liturgy of the Word we proclaim the Gospel of Christ, first in the reading from the Old Testament, in the singing of the Psalm, reading from the Epistles of the Church and finally, in the proclamation of the Gospel itself.

Although Jesus was born after, we are reminded that the Old Testament points toward Him and is given so that we might recognize and know Him.  It is a reading of the Gospel, veiled.