9 Now David knew that Saul was plotting evil against him; so he said to Abiathar the priest, “Bring the ephod here.” 10 Then David said, “O Lord God of Israel, Your servant has heard for certain that Saul is seeking to come to Keilah to destroy the city on my account. 11 Will the men of Keilah surrender me into his hand? Will Saul come down just as Your servant has heard? O Lord God of Israel, I pray, tell Your servant.” And the Lord said, “He will come down.” 12 Then David said, “Will the men of Keilah surrender me and my men into the hand of Saul?” And the Lord said, “They will surrender you.” 13 Then David and his men, about six hundred, arose and departed from Keilah, and they went wherever they could go. When it was told Saul that David had escaped from Keilah, he gave up the pursuit. 1 Samuel 23:9-13
God told David that Saul would come after him, and that the people of Keilah would give him up. Yet neither of these things happened.
Since God does know the future, this prophecy must have been a conditional on David’s response. The if was implied. If you don’t leave, Saul will come and the Keilahites will give you up. David heeded the implied warning and left.
Many of the warnings and promises of the prophets are similarly conditional. If you obey me, these are the blessings you will receive. If you rebel against me, these are the punishments I will mete out. Sometimes the conditions of these promises and warnings are spelled out, but not always.
Many if not most prophecies to ancient Israel, for example, were conditional. Before we assume that a prophecy is yet to be fulfilled, we need to check scripture and history to see if the prophecy has been fulfilled. If it has not been fulfilled, we need to check scripture and history again to see if the conditions for the prophecy have been fulfilled.
– SSXG