Whether things known or declared prophetically can be false?

❌ Objection 1 : It would seem that things known or declared prophetically can be false. For prophecy is about future contingencies, as stated above (Article [3]). Now future contingencies may possibly not happen; else they would happen of necessity. Therefore the matter of prophecy can be false.

❌ Objection 2 : Further, Isaias prophesied to Ezechias saying (Is. 38:1): "Take order with thy house, for thou shalt surely die, and shalt not live," and yet fifteen years were added to his life (4 Kgs. 20:6). Again the Lord said (Jer. 18:7,8): "I will suddenly speak against a nation and against a kingdom, to root out and to pull down and to destroy it. If that nation against which I have spoken shall repent of their evil, I also will repent of the evil that I have thought to do them." This is instanced in the example of the Ninevites, according to Jn. 3:10: "The Lord [Vulg.: 'God'] had mercy with regard to the evil which He had said that He would do to them, and He did it not." Therefore the matter of prophecy can be false.

❌ Objection 3 : Further, in a conditional proposition, whenever the antecedent is absolutely necessary, the consequent is absolutely necessary, because the consequent of a conditional proposition stands in the same relation to the antecedent, as the conclusion to the premises in a syllogism, and a syllogism whose premises are necessary always leads to a necessary conclusion, as we find proved in I Poster. 6. But if the matter of a prophecy cannot be false, the following conditional proposition must needs be true: "If a thing has been prophesied, it will be." Now the antecedent of this conditional proposition is absolutely necessary, since it is about the past. Therefore the consequent is also necessary absolutely; yet this is unfitting, for then prophecy would not be about contingencies. Therefore it is untrue that the matter of prophecy cannot be false.