Most people in the traditional church today have been taught that prophetic words are unconditional--that if God said it, it is bound to happen regardless of what people believe, say, or do. If we search the scriptures and rightly divide the Word of God we find that this is not so. God says in Deuteronomy 13 that some false prophets gave signs which did happen while words that God spoke--that are recorded as being words from God in the Word of God--did not come to pass because the circumstances or conditions for that word to come to pass were changed.
Jonah was given a word from God and was almost killed when he refused to deliver the word that God was speaking to Nineveh. However, God saved his life through a fish and he got to speak the word of the Lord to the city. “Yet forty days, and Nineveh shall be overthrown.” (Jonah 3:4) This was the word of the Lord yet it never came to pass because the circumstances changed. The people believed it and changed, and their change changed God.
Hebrews 4:2 says:”For unto us was the gospel (the good news) preached (prophesied), as well as unto them: but the word preached (prophesied) did not profit them, it not being mixed with faith.” Prophetic words will only profit us if we believe and receive them. In the case of Nineveh, it was profitable for them that the prophetic word did not come to pass. This is really the main reason that God speaks to us, that we profit from his life giving prophetic words.
Hezekiah was told by a prophetic word that he was going to die, yet God added 15 years to his life according to 2 Kings 20.
The children of Israel were promised land through the prophetic word of the Lord but only Joshua and Caleb entered into the promised land. Why? Because they believed the words and acted accordingly.
In the parable of the sower in Mark chapter 4 we see that the word will produce in accordance with how it is received. This is indeed true of the prophetic word of God and is the condition that determines how much of it will come to pass.
The prophetic ministry of the Lord will never be able to operate in the church before the church is taught how to treat it. Some people think that if God speaks through someone it will always be perfect not realizing that that particular word is filtered through an imperfect human being. So the bible tells us to try prophetic speech (through the scriptures) and hold fast to that which is good. (1 Thess. 5:20)