The Cow - 2:39
And those who deny and disbelieve in Our signs are condemned to the Fire; they will abide therein forever.
The eternity of Paradise and Hell:
Prophet Abraham/14:48
On the Day when the earth is replaced by another earth and the heavens by other heavens, and everyone is brought before Allah, the One and the Most High.
Prophet Hud/11:106
The unfortunate are in the Fire. They will groan therein.
Prophet Hud/11:107
They will abide therein as long as the heavens and the earth endure, except if your Lord wills. Your Lord is the Doer of whatever He wills
Prophet Hud/11:108
And those who deserve happiness will abide in Paradise as long as the heavens and the earth endure. Except if your Lord wills. This is an uninterrupted reward.