This is written by Saint Ambrose to his sister, Marcellina, about the evening psalmody with reference to Pythagoras.
“But I wish also that even in your bedchamber you weave together psalms with the Lord’s prayer in frequent interchange, both as you stand vigil and before drowsiness suffuses your body; so that at the very beginning of rest sleep finds your free from anxiety over secular affairs and meditating upon those of heaven. And indeed he who first coined the name of philosophy itself, bade the tibia player, each day before goint go bed, to play soothing tunes, in order to still his heart, disturbed by worldly cares. Yet he, like one who washes bricks, sought in vain to banish secular matters with secular means.”
The angel shall guard me,
Mark me with the holy cross.
Hear, my ear, hear Angels singing,
The Lord Jesus is calling our souls to the bridal chamber.
We commend our souls Into the hands of our holy angels
Let us offer our souls!
Let them be counted in the heavenly holy hosts.
Let us rejoice that we may be comforted in the holy name of the Lord Jesus!