Jonathan Edwards

"“If the heart be chiefly and directly fixed on God, and the soul engaged to glorify him, some degree of religious affection will be the effect and attendant of it. But to seek after affection directly and chiefly; to have the heart principally set upon that; is to place it in the room of God and his glory. If it be sought, that others may take notice of it, and admire us for our spirituality and forwardness in religion, it is then damnable pride; if for the sake of feeling the pleasure of being affected, it is then idolatry and self-gratification.”
― Jonathan Edwards, The Life and Diary of David Brainerd

St. Thomas Aquinas

“Since faith rests upon infallible truth, and since the contrary of a truth can never be demonstrated, it is clear that the arguments brought against faith cannot be demonstrations, but are difficulties that can be answered.”