The third sign is that these words do not vanish from the memory for a very long time: some, indeed, never vanish at all. Words which we hear on earth -- I mean, from men, however weighty and learned they may be -- we do not bear so deeply engraven upon our memory, nor, if they refer to the future, do we give credence to them as we do to these locutions. For these last impress us by their complete certainty, in such a way that, although sometimes they seem quite impossible of fulfilment, and we cannot help wondering if they will come true or not, and although our understanding may hesitate about it, yet within the soul itself there is a certainty which cannot be overcome. It may seem to the soul that everything is moving in the contrary direction to what it had been led to expect, and yet, even if many years go by, it never loses its belief that, though God may use other means incomprehensible to men, in the end what He has said will come true; as in fact it does. None the less, as I say, the soul is distressed when it sees things going badly astray. It may be some time since it heard the words; and both their working within it and the certainty which it had at the time that they came from God have passed away. So these doubts arise, and the soul wonders if the whole thing came from the devil, or can have been the work of the imagination. Yet at the time it had no such doubts and it would have died in defence of their veracity. But, as I say, all these imaginings must be put into our minds by the devil in order to distress us and make us fearful, especially if the matter is one in which obeying the locutions will bring others many blessings, or produce good works tending greatly to the honour and service of God but presenting considerable difficulties. What will the devil not do in this case by encouraging such misgivings? At the very least he will weaken the soul's faith, for it is most harmful not to believe that God is powerful and can do works which are incomprehensible to our understanding.