St. Augustine of Hippo (+430) is often quoted as having said "He who sings, prays twice." The Latin cited for this is "Qui bene cantat bis orat" or "He who sings well prays twice".
Actually, this does not appear in anything of St. Augustine that has come down to us. He did write, "cantare amantis est… Singing belongs to one who loves" (s. 336, 1 – PL 38, 1472). That is often invoked as the source of qui bene cantat bis orat.
In the Vatican’s online English version of the CCC there is a note: "Eph 5:19; St. Augustine, En. in Ps. 72,1: PL 36, 914; cf. Col 3:16."
Also, this is quoted in the Latin CCC 1156 as "qui canit bis orat". In the Latin edition of the CCC we are sent then to footnote n. 26 (oddly, this is note 21 in the newer English edition, which adds a confer reference to Col. 3:16 – which is not in the Latin CCC). Latin CCC 1156, note 26 reads:
Cf. Sanctus Augustinus, Enarratio in Psalmum 72, 1: CCL 39, 986 (PL 36, 914).
Having written my thesis on Augustine I decided to dig into this. I happen to have my trusty CCL 39 nearby. Looking up that reference we find what Augustine really said:
Qui enim cantat laudem, non solum laudat, sed etiam hilariter laudat; qui cantat laudem, non solum cantat, sed et amat eum quem cantat. In laude confitentis est praedicatio, in cantico amantis affectio…For he who sings praise, does not only praise, but also praises joyfully; he who sings praise, not only sings, but also loves Him whom he is singing about/to/for. There is a praise-filled public proclamation (praedicatio) in the praise of someone who is confessing/acknowledging (God), in the song of the lover (there is) love.
This is a very interesting passage. Augustine is saying that when the praise is of God, then something happens to the song of the praiser/love that makes it more than just any kind of song. The object of the song/love in a way becomes the subject. Something happens so that the song itself becomes Love in its manifestation of love of the one who truly is Love itself.
However,… it does not say qui canit bis orat. There seems to have been some confusion of the verbs laudare and orare.
I can still say with the oft quoted citation: "He who sings well prays twice", so long as it is from love.