Another point I wanted to share regarding paradise being eternal
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Ayaa 51 - 60 of As-Saaffat (37), talks about a person looking at his friend in hell from paradise, and after he looked at him, he says this, "Is it then that we are not going to die" (37:58), if it was not eternal, then they would eventually die, but here it says that we are not going t die, thus suggesting an eternal paradise.