The Lord told Moses twice that He would destroy Israel and start over with Moses. Did He? No, He did not do what He said He would do.
Is He a liar? No, He changed His mind.
The Lord said He would without fail drive the Hittites, the Hivites, the Jebusites -- all of the 'Ites -- out of the Promised Land. Did He? No, He did not. And later, He said in the first person that He had promised He would but that he didn't do what He promised. He changed His mind.
The Lord promised King Nebuchadnezzer that he would destroy Tyre completely, and everything they had would be his. Never happened. Is God a liar? Don't think so.
Then, God told King Neb that He had promised that to him, but that it hadn't come to pass, so instead He would deliver Egypt to him.
Again, never happened. Why? Free will - Nebuchadnezzer was on his way to Egypt, but turned around and chose to go home when he heard his father died. It didn't come about as stated.
The Holy Spirit prophecied through a prophet to Paul that if he went to Jerusalem, the Jews there would bind Paul's hands and feet and give him to the Romans. What happened?
Paul went there, and the Jews tried to kill him, so a Roman guard rode in, rescued Paul from the Jews and took him into custody against the will of the angry Jews there.
Was the Holy Spirit a liar? No. Human free will changed the situation. God expected one thing to happen, but it ended up happening the opposite way from how it was prophecied.
In each of these situations, did God fail? No, in many cases, men failed. And God worked from that. In the case of Nebuchadnezzer and Egypt, he simply chose in the end to not accept the gift God promised Him. If Nebuchadnezzer had continued on to Egypt, he would have conquered it. But he decided to go home after his father's death.
God doesn't fail. People do. And He responds to that.
