Taqdeer
Predestination is in fact, the advanced knowledge of God. It means He did not make something happen, but something was going to happen and He knew it in advance. Before Adam committed the mistake, God had already announced that he created a man to be sent to the world. Adam was kept for a while in a garden and after that, He was going to be sent to the world. But he committed a mistake and was expelled. If he had not committed the mistake, still he had to go to the world for the test. Read the full story in Surah Baqarah.
As already told, Adam was made to go to the world. Allah would have sent him on his time honorably. Therefore, He warned him not to let the Devil expel you from there.