A Scriptural Example
Conditional prophecy is legitimate prophecy that sometimes does not come to pass.
Prophecy that has to do with human behavior and circumstances that can change because of human behavior, is always conditional.
In 1 Samuel 23 it is the very words of Jehovah that do not come to pass:
1 Sam 23:6-13
6 And it came to pass, when Abiathar the son of Ahimelech fled to David to Keilah, that he came down with an ephod in his hand.
7 And it was told Saul that David was come to Keilah. And Saul said, God hath delivered him into mine hand; for he is shut in, by entering into a town that hath gates and bars.
8 And Saul called all the people together to war, to go down to Keilah, to besiege David and his men.
9 And David knew that Saul secretly practised mischief against him; and he said to Abiathar the priest, Bring hither the ephod.
10 Then said David, O Lord God of Israel, thy servant hath certainly heard that Saul seeketh to come to Keilah, to destroy the city for my sake.
11 Will the men of Keilah deliver me up into his hand? will Saul come down, as thy servant hath heard? O Lord God of Israel, I beseech thee, tell thy servant. And the Lord said, He will come down.
12 Then said David, Will the men of Keilah deliver me and my men into the hand of Saul? And the Lord said, They will deliver thee up.
13 Then David and his men, which were about six hundred, arose and departed out of Keilah, and went whithersoever they could go. And it was told Saul that David was escaped from Keilah; and he forbare to go forth.
Saul did not come to Keliah, and the people of Keliah did not offer David up, because David left Keliah. Then, Saul heard about David’s departure, so he did not go to Keliah.
The failure of the prophecy to come to pass in this instance, had nothing to do with the integrity of God, the one who spoke the prophecy.
This prophecy was not the Word of Jehovah, but truth about circumstances that existed in the temporal world at that moment.
The prophecy was true at the moment that Jehovah spoke it, but the circumstances changed after David prayed;
David’s behavior changed after he received counsel from Jehovah, and left Keliah; and
Saul’s behavior changed after he heard that David left Keliah.
Prophecy that is the Word of Jehovah, however, about what Jehovah says that He will or will not do, must come to pass, or the prophet is a false prophet.
22 When a prophet speaketh in the name of the Lord, if the thing follow not, nor come to pass, that is the thing which the Lord hath not spoken, but the prophet hath spoken it presumptuously: thou shalt not be afraid of him.
However, Jehovah can have mercy and change His own Word, if he wants to.
If the nation repents, the judgment can be cancelled:
1 And the word of the Lord came unto Jonah the second time, saying,
2 Arise, go unto Nineveh, that great city, and preach unto it the preaching that I bid thee.
3 So Jonah arose, and went unto Nineveh, according to the word of the Lord. Now Nineveh was an exceeding great city of three days' journey.
4 And Jonah began to enter into the city a day's journey, and he cried, and said, Yet forty days, and Nineveh shall be overthrown.
5 So the people of Nineveh believed God, and proclaimed a fast, and put on sackcloth, from the greatest of them even to the least of them.
6 For word came unto the king of Nineveh, and he arose from his throne, and he laid his robe from him, and covered him with sackcloth, and sat in ashes.
7 And he caused it to be proclaimed and published through Nineveh by the decree of the king and his nobles, saying, Let neither man nor beast, herd nor flock, taste any thing: let them not feed, nor drink water:
8 But let man and beast be covered with sackcloth, and cry mightily unto God: yea, let them turn every one from his evil way, and from the violence that is in their hands.
9 Who can tell if God will turn and repent, and turn away from his fierce anger, that we perish not?
10 And God saw their works, that they turned from their evil way; and God repented of the evil, that he had said that he would do unto them; and he did it not.
If a person repents, the judgment can be cancelled:
2 Kings 20:1-11
1 In those days was Hezekiah sick unto death. And the prophet Isaiah the son of Amoz came to him, and said unto him, Thus saith the Lord, Set thine house in order; for thou shalt die, and not live.
2 Then he turned his face to the wall, and prayed unto the Lord, saying,
3 I beseech thee, O Lord, remember now how I have walked before thee in truth and with a perfect heart, and have done that which is good in thy sight. And Hezekiah wept sore.
4 And it came to pass, afore Isaiah was gone out into the middle court, that the word of the Lord came to him, saying,
5 Turn again, and tell Hezekiah the captain of my people, Thus saith the Lord, the God of David thy father, I have heard thy prayer, I have seen thy tears: behold, I will heal thee: on the third day thou shalt go up unto the house of the Lord.
6 And I will add unto thy days fifteen years; and I will deliver thee and this city out of the hand of the king of Assyria; and I will defend this city for mine own sake, and for my servant David's sake.
7 And Isaiah said, Take a lump of figs. And they took and laid it on the boil, and he recovered.
8 And Hezekiah said unto Isaiah, What shall be the sign that the Lord will heal me, and that I shall go up into the house of the Lord the third day?
9 And Isaiah said, This sign shalt thou have of the Lord, that the Lord will do the thing that he hath spoken: shall the shadow go forth ten degrees, or go back ten degrees?
10 And Hezekiah answered, It is a light thing for the shadow to go down ten degrees: nay, but let the shadow return backward ten degrees.
11 And Isaiah the prophet cried unto the Lord: and he brought the shadow ten degrees backward, by which it had gone down in the dial of Ahaz.