"The saints found more pleasure in reciting the Office than worldly people find in the midst of pastimes and amusements"
--Saint Alphonsus Liguori
The Divine Office, together with the Holy Mass forms the public prayer of the Church. It aims to sanctify the day and follow the command to pray without ceasing (cf. 1 Thessalonians 5:17). We can find the tradition of praying at certain times of the day, going at least as far back as the first Apostles (cf. Acts 3:1).A more structured form based on the Psalms first appeared with the emergence of early monastic communities, and remained in the Church ever since.
The form most commonly used today took its shape during the Second Vatican Council. Offices became shorter, and the use of vernacular, rather than Latin was permitted. This created the possibility for laity to join in the prayer of the Church which previously was mainly practised by priests and religious.
Morning, Evening and Night prayers include Gospel canticle. The Morning prayer recalls the prayer of praise exclaimed by Zechariah at the circumcision of St John the Baptist (Luke 2:68-79). In the Evening, we pray together with Our Lady in the Magnificat (Luke 1:47:55) - a prayer expressing love and complete trust is God. And at night, we remember the prayer of Simeon who could see in baby Jesus "a light to enlighten the pagans and the glory of Israel" (Luke 2:29-32).
You can view the text of daily offices on the Universalis website.