Why evening? Three saints give testimony:
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.” [Basil the Great, Regulae fusius tractatae resp. 37, 3: PG 31, 1015.] 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.” [See Ps 141:2.] 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.” [John Cassian, De institutione coenob. 3, 3: PL 49, 124, 125.] 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.” [Cyprian, De oratione dominica 35: PL 4, 560.] 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. . . .”
Vespers has a slightly stonger appeal that Lauds. I suspect the setting of the sun and the coming of twilight reflects the mortal experience more directly. Quite often we begin with optimism and high hopes in life. But the daylight soon ends, the shadows deepen, and our attempts at discernment muffle with the dimming light.
Vespers appeals to the reality that the light does dim, death does come, and despite our best intentions, we frequently come to difficulty in making the right choices in life.
O radiant Light, O sun divine
Of God the Father’s deathless face,
O image of the light sublime
That fills the heav’nly dwelling place.
O Son of God, the source of life,
Praise is your due by night and day;
Unsullied lips must raise the strain
Of your proclaimed and splendid name.
Lord Jesus Christ, as daylight fades,
As shine the lights of eventide,
We praise the Father with the Son,
The Spirit blest and with them one.