"Omnis enim res, quae dando non deficit, dum habetur et non datur, nondum habetur, quomodo habenda est."English translation:
"For if a thing is not diminished by being shared with others, it is not rightly owned if it is only owned and not shared."German translation:
"Denn jede Sache, die durch Mitteilung an andere nicht verliert, besitzt man nicht, wie man soll, solange man sie nur selber besitzt, ohne sie wieder an andere weiterzugeben."(from Sigisbert Mitterer, Bibliothek der Kirchenväter, Bd. 49, München 1925)
This quote can be found in Book I, Chapter 1 "De doctrina christiana" "Corpus Christianorum", "Series latina", Vol. 32, p. 6, lines 10-11. Written 397 AD by Saint Augustinus.
It originally referred to the principle of giving and sharing preached by Jesus but fits almost perfectly on the philosophy of Free Software where one can share without losing.
Due to his role in the dogmatic controversies and his far-spanning work, Augustinus has been seen as the theological authority in the medieval ages. Nowadays he is held as the most important latin found-father of the church.
Many thanks to