ChapterII-II. Morning Prayer and Evening Prayer
37. "By the venerable tradition of the universal Church, lauds as morning prayer and vespers as evening prayer are the two hinges on which the daily office turns; hence they are to be considered as the chief hours and celebrated as such." 
38. As is clear from many of the elements that make it up, morning prayer is intended and arranged to sanctify the morning. St. Basil the Great gives an excellent description of this character in these words: "It is said in the morning in order that the first stirrings of our mind and will may be consecrated to God and that we may take nothing in hand until we have been gladdened by the thought of God, as it is written: 'I was mindful of God and was glad' (Ps 77:4 [Jerome's translation from Hebrew]), or set our bodies to any task before we do what has been said: 'I will pray to you, Lord, you will hear my voice in the morning; I will stand before you in the morning and gaze on you' (Ps 5:4-5)." 
Celebrated as it is as the light of a new day is dawning, this hour also recalls the resurrection of the Lord Jesus, the true light enlightening all people (see Jn 1:9) and "the sun of justice" (Mal 4:2), "rising from on high" (Lk 1:78). Hence, we can well understand the advice of St. Cyprian: "There should be prayer in the morning so that the resurrection of the Lord may thus be celebrated." 
39. When evening approaches and the day is already far spent, evening prayer is celebrated in order that "we may give thanks for what has been given us, or what we have done well, during the day."  We also recall the redemption through the prayer we send up "like incense in the Lord's sight," and in which "the raising up of our hands" becomes "an evening sacrifice."  This sacrifice "may also be interpreted more spiritually as the true evening sacrifice that our Savior the Lord entrusted to the apostles at supper on the evening when he instituted the sacred mysteries of the Church or of the evening sacrifice of the next day, the sacrifice, that is, which, raising his hands, he offered to the Father at the end of the ages for the salvation of the whole world."  Again, in order to fix our hope on the light that knows no setting, "we pray and make petition for the light to come down on us anew; we implore the coming of Christ who will bring the grace of eternal light."  Finally, at this hour we join with the Churches of the East in calling upon the "joy-giving light of that holy glory, born of the immortal, heavenly Father, the holy and blessed Jesus Christ; now that we have come to the setting of the sun and have seen the evening star, we sing in praise of God, Father, Son, and Holy Spirit. . . ."
40. Morning prayer and evening prayer are therefore to be accorded the highest importance as the prayer of the Christian community. Their public or communal celebration should be encouraged, especially in the case of those who live in community. Indeed, the recitation of these hours should be recommended also to individual members of the faithful unable to take part in a celebration in common.
41. Morning prayer and evening prayer begin with the introductory verse, God come to my assistance. Lord, make haste to help me. There follows the Glory to the Father, with As it was in the beginning and Alleluia (omitted in Lent). This introduction is omitted at morning prayer when the invitatory immediately precedes it.
42. Then an appropriate hymn is sung immediately. The purpose of the hymn is to
set the tone for the hour or the feast and, especially in celebrations with a congrega
tion, to form a simple and pleasant introduction to prayer.
43. After the hymn the psalmody follows, in accordance with the rules laid down in nos. 121-125. The psalmody of morning prayer consists of one morning psalm, then a canticle from the Old Testament and, finally, a second psalm of praise, following the tradition of the Church.
The psalmody of evening prayer consists of two psalms (or two parts of a longer psalm) suited to the hour and to celebration with a congregation and a canticle from the letters of the apostles or from the Book of Revelation.
44. After the psalmody there is either a short reading or a longer one.
45. The short reading is provided to fit the day, the season, and the feast. It is to be read and received as a true proclamation of God's word that emphasizes some holy thought or highlights some shorter passages that may be overlooked in the continuous cycle of Scripture readings.
The short readings are different for each day of the psalter cycle.
46. Especially in a celebration with a congregation, a longer Scripture reading may be chosen either from the office of readings or the Lectionary for Mass, particularly texts that for some reason have not been used. From time to time some other more suitable reading may be used, in accordance with the rules in nos. 248-249 and 251.
47. In a celebration with a congregation a short homily may follow the reading to explain its meaning, as circumstances suggest.
48. After the reading or homily a period of silence may be observed.
49. As a response to the word of God, a responsorial. chant or short responsory is provided; this may be omitted. Other chants with the same purpose and character may also be substituted in its place, provided these have been duly approved by the conference of bishops.
50. Next is the solemn recitation of the gospel canticle with its antiphon, that is, the Canticle of Zechariah at morning prayer and the Canticle of Mary at evening prayer. Sanctioned by age-old popular usage in the Roman Church, these canticles are expressions of praise and thanksgiving for our redemption. The antiphon for each canticle is indicated, according to the character of the day, the season, or the feast.
51. After the canticle, at morning prayer come the petitions for the consecration of the day and its work to God and at evening prayer, the intercessions (see nos. 179-193).
52. After the petitions or intercessions the Lord's Prayer is said by all.
53. Immediately after the Lord's Prayer there follows the concluding prayer, which for weekdays in Ordinary Time is found in the psalter and for other days in the proper.
54. Then, if a priest or deacon is presiding, he dismisses the congregation with the greeting, The Lord be with you, and the blessing as at Mass. He adds the invitation, Go in peace. R. Thanks be to God. In the absence of a priest or deacon the celebration concludes with May the Lord bless us, etc.