More properly, since the liturgy is also a profession of eternal truths, and subject, as such, to the supreme teaching authority of the Church, it can supply proofs and testimony, quite clearly, of no little value, towards the determination of a particular point of Christian doctrine.
More accurately, since the liturgy also affirms eternal truths and is subject to the supreme teaching authority of the Church, it can provide proofs and testimony, of considerable value, in determining a specific point of Christian doctrine.