Surah 38. Sad, Ayah 81

The grant of "respite" to Iblis implies that he would have the power to tempt man until the end of time.

It is not an indefinite respite. It is for a period definitely limited, while this our Probation lasts in this world. It is part of the test as to how we use our limited free-will. After that, our whole existence will be on a different plane. The good will have been sorted out, the chain of consequences of the present world will be broken, and "a new Creation" will have taken the place of the present World.