Image, One faith, St. Paul writes (Eph. 4:5). Hold most firmly that our faith

One faith, St. Paul writes (Eph. 4:5). Hold most firmly that our faith is identical with that of the ancients. Deny this, and you dissolve the unity of the Church … We must hold this for certain, namely: that the faith of the people at the present day is one with the faith of the people in past centuries. Were this not true, then we would be in a different church than they were in and, literally, the Church would not be One.

Thomas Aquinas

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