As the day is given to God at its rising, so it is returned to Him at its setting. The evening prayers close the day: thanksgiving for what was given, a quiet examination of where one fell, the asking of forgiveness, and the commending of sleep, that small nightly rehearsal of death, into God's keeping.
The Church has always prayed as the light declines. The Song of Simeon, “Lord, now lettest Thou Thy servant depart in peace,” is an evening prayer, and so is the plea that the night be passed in peace and the morning found in mercy. To end the day this way is to refuse to carry its burdens into sleep, laying them instead where they belong.
The evening rule includes a brief looking-back over the day, not to accuse the self, but to bring what was missed to God, and to carry the heavier things toward confession. It ends, as the whole life should, in peace: nothing clung to, everything entrusted.