If time is a feature of this creation, and souls of the dead live outside this creation, then by definition they do not experience time. So they are eternal. Perhaps they can observe creation (and therefore can observe all points in time). It’s hard to imagine how anything would be temporary in a realm where there is no time.
I think it’s clearly true that the time we experience is a feature of this creation. However, that doesn’t mean there’s no time in heaven. It’s just that time in heaven is quite independent of time on earth. Here’s a story that may illustrate the point —
I was in the hospital’s sleep lab, prepped for a sleep apnea test, and found myself doped up on sleeping pills. Sometimes the pills keep from dreaming, but sometimes they trigger the strangest dreams …
A guide led me into a gigantic room, so large I couldn’t see the walls. I didn’t know who the guide was, but he (or she?) was clearly some sort of heavenly being.
The guide showed me a row of globes — thousands (or millions?) of planet earths in a row going far beyond what I could see.
The guide urged me to look at one, and as I looked, I found I could look as closely as I liked. I could see the rivers, the trees, even houses and people. I was amazed!
Out of curiosity, I stuck a finger into a peninsula, and I saw water rush into the area once occupied by land. The guide was furious! He told me to look at the globes nearby in both directions, and I saw that, while the globes to my left were unchanged, the globes to my right now all had the same finger hole in the peninsula. As I looked more closely, I saw houses being rebuilt from tidal waves, funerals for thousands, and boats and trucks delivering water and food to starving people.
For the first time, I realized it was all real. Those were real people with real lives. I don’t know how many I killed, but it was big number!
I found myself in tears, crying to the guide. “I had no idea! I thought these globes were some kind of simulation. I didn’t mean to kill anyone! Tell me how to fix this, please!”
The guide, still very angry, explained that this was the same planet on which I lived. He was showing me earth from God’s viewpoint — outside time — and they had plainly entrusted God’s powers to an unworthy person!
He told me that I should take some time to think about what I’d done. “But,” I said, “I need to fix this problem now! People are suffering. People have died!”
The guide explained with obvious impatience, “Don’t you understand even now? Time passes here, but it’s not the same as time on earth. Take all the time you need.”
I still didn’t understand, but I took a walk, calmed down, and some hours (years?) later, I starting running past the globes to the left. I ran until I found a globe with no people living on or even near the peninsula. And I stuck my finger in it, just like before. Once again, water rushed into the hole, but no one was hurt. No one was even there to see the change.
I then ran to the globe where I first made the hole, and saw that there was no damage, no death, and no suffering. Rather, huge cities had been built on the shoreline of my fingerhole. Navies sailed the fingerhole sea. My damage had been undone!
The guide grabbed me. “That’s enough. You’re not God and you don’t know what you’re doing. You didn’t even look to see what future you were destroying! Destroying something bad today may destroy a greater good in the future. What’s the point of having the power to see the future if you don’t use it to make wise decisions?
“I’m afraid you’re not worthy. Your stay here will be but temporary. God will have to fix your mistakes, but you’ll be glad to know that he can … and will. You’re going home, back to the time from which you left.”
At that moment, a nurse woke me up. “It’s 6:00. You had about 5 hours of sleep. Do you feel rested?”