necessary condition

“Faventinus), etc. Gradually this mass of glosses took on in the schools a permanent form, a necessary condition to its usefulness in teaching; and became a kind of secondary canonical text, less authoritative, of course, than the original, but supplying material for oral commentary.”

The Catholic Encyclopedia, Volume 6: Fathers of the Church-Gregory XI

“F. Faith, presupposes the "drawing of the Father," 106, 266; different stages of, 138, 165, 174, 433; the necessary condition of aid from”

The Life of Jesus Christ in Its Historical Connexion and Historical Developement.