First, the earth in the Millennium is not Heaven. So all lives will still die during the Millennium.
Okay, however, if that chapter of Isaiah is used that way then it can not ALSO be used to justify a view that in a perfect world, animals will not eat each other therefore animals eating each other is not perfect. I’m not saying you used it that way, but I’ve seen it referenced as such in many other discussions.
Second, this is why we need to consider that plants and cells may not be treated as lives by God. Plants are created separately from animals. They are food for real lives.
However, that doesn’t fit in with the view of Jesus we can see through his parables. Take the parable of the sower who cast his seed on many grounds. On some the crows at it, on some it withered, on some the thorns choked it out and killed it, and on some it grew on fertile ground and produced 100sfold. But it can’t be KILLED unless it was ALIVE. There are more examples of such.
Also, either it’s ALL life, or none. There is no purpose in thinking that only animal death counts EXCEPT to try and find an unsupported loophole. It can’t grow and be fertile and reproduce and flower unless it is ALIVE. And if it is alive, and then eaten, it dies. PERIOD.
Third, the Garden of Eden is not Heaven either. I don't think animals will be in the Heaven. Sorry if you have pets.
Yes, it is true the Garden was not Heaven, but the question was not “Is Heaven perfect” but ‘Is/was the Garden and God’s creation perfect?’
Fourth, who said that there were animals in the Garden? The Garden is a place God sets for Adam (and Eve). Animals might exist outside the Garden, where they may die.
The Bible says so. The serpent is an animal. All the animals were brought TO the man in Gen 2:19 for him to name them. And if outside the Garden is not perfect, the question of God creating imperfection STILL remains because the outside of the Garden was imperfect.
Oh, and also, at the end of Genesis 3, God creates garments of skins for Adam and Eve. Skins only come from dead animals. So either God created already dead things before driving them from the Garden (which would straight up mean that death is not imperfect since God can create things only resulting from it, namely dead animal skins), or God actually slew animals to make said garments.
Also, I know you didn’t address it, but I WOULD like to stress my point about sperm. It would be impossible for nearly any animal to reproduce without wasting a great many sperm in the process, humanity included. And the death of sperm would be death of something animal. And it would be impossible for any creature to fulfill God’s command without said death being involved. Whether you believe God created Eden directly or created all life indirectly, God still is responsible for designing reproduction to work that way, so He made it impossible to reproduce without death occurring, and could thus not fulfill God’s command without death occurring, so God commanded something that would end in death of one sort or another.
Metherion