And now, my brethren, who are not Catholics, perhaps you will tell me, that, if all inquiry is to cease when you become Catholics, you ought to be very sure that the Church is from God before you join it. You speak truly; no one should enter the Church without a firm purpose of taking her word in all matters of doctrine and morals, and that, on the ground of her coming directly from the God of Truth.
--Blessed John Henry Newman, “Faith and Doubt”