Basically, it goes like this: If, in this life, we can choose where we want to live in the future, (Heaven or Hell) but we can't choose a different option once we are there, then we must not really be free. If God gives us freedom, why doesn't he make that freedom permanent? If God can remove our freedom in the future, why must He give us freedom now? If God allows us to choose either Heaven or Hell during this life, then why does He take that choice away once we're in Heaven? On Earth, I'm free to choose Heaven or Hell because God gave me this freedom, but in Heaven I'm not free to choose Heaven or Hell because God removed this freedom. That's the argument.
But this argument really fails on a few levels. First of all, it's really quite misleading to say that we choose Heaven or Hell in this life. There's no denying that the choice we make in this life results in Heaven or Hell. But we don't actually choose Heaven or Hell directly. Our choice is between believing the gospel or not believing the gospel. The Heaven or Hell part is really God's predetermined choice, not ours. That is, God decides that whoever believes the gospel will go to Heaven and whoever doesn't believe the gospel will go to Hell. To say that we choose Heaven or Hell directly is to erect a straw man.
The distinction here is subtle, but important. The effect of a choice is not the same as the choice itself. I can agree that we are "effectively" choosing Heaven or Hell. But the effects are what they are because of God's choice, not because of my choice. So it creates confusion to say that we're choosing Heaven or Hell. We're not. Nobody chooses Hell. God chooses Hell for everyone who does not choose to believe the gospel. Oh, sure… people want to rebel against God and they choose to do so… no dispute there. But nobody chooses to go to Hell. They choose not to trust in Christ, they choose to continue in their rebellion, and the effect of that choice is that they wind up in Hell.
This simple distinction really knocks the legs out from under the argument. But we can go further…
Even if we grant that our direct choice in this life is between Heaven and Hell, the case still cannot be made that our "choice is taken away" in Heaven because at the point that we "choose Heaven," we understand that Heaven is a place we won't be able to leave. And it's worth pointing out that we also understand that Heaven is a place we won't want to leave, and this is precisely why we would choose it. In other words, if we grant (for the sake of argument) that we directly choose Heaven or Hell, you could say that, when we choose to believe the gospel, we choose to forfeit the choice to leave Heaven. So even if we grant the premise, God can be seen to honor our choice by not allowing us to leave Heaven.
Even so, we shouldn't approach the question from such an invalid starting point. We should approach with the understanding that Heaven or Hell are consequences; effects; results of our choice either to believe the gospel or continue to reject it, and that God's plan of salvation makes salvation available to us during this life only and that salvation (Heaven) is the result of our choice to believe the gospel, not a result of our choosing Heaven.
If we choose Heaven directly, then everyone who chooses Heaven will go there. I'm aware of a particular passage where assorted individuals are "choosing Heaven" in the direct sense and yet they're driven away by Christ. That is, these folks want in. They've chosen Heaven. The passage I'm thinking of is Matthew 7:21-23. This passage illustrates the unfortunate reality that lots of people "choose Heaven" directly and yet never get there. Why? Because although they chose to go to Heaven, they did NOT choose to trust in Christ but chose instead to trust in their works. And as a result, Christ ordered them to depart from Him. If we simply "choose Heaven" then Christ should have let those folks in. This underscores the important distinction between our direct choice and the effects or consequences of our choice. Those people chose to trust in their works rather that trust in Christ and as a result of this, Christ refused them. They chose Heaven, but ended up in Hell.
Essentially, this characterization of choosing Heaven or choosing Hell and God "taking our choice away" once we're in Heaven as an argument against Libertarian freedom is really a straw man and like any straw man argument, it fails spectacularly. There's a deep-seated desire to portray the Libertarian view as having elevated man to a position where he calls the shots. But what we see here is that man doesn't call the shots, he merely makes a choice: Believe the gospel, or continue to reject it.
Also related to this question of God "taking our freedom away," it's important to understand that God's plan of salvation is only available to us in this life. When we check out of this life, the opportunity for salvation has passed.
Hebrews 9:27: And as it is appointed for men to die once, but after this the judgment.
This means that when we pass from this life to the next, our fate is sealed one way or the other. There is no plan of salvation beyond that point. People in Hell don't have any further opportunity to be saved. This life is it. And those are the rules God put in place… there's nothing we can do to change them. He determines the consequences of our choices and in that way, He remains in charge. No one's usurping His authority. And the consequences, as God has determined it, are permanent either way.
We deal with this sort of thing regularly in the course of everyday life. It's why we have expressions like "Hindsight's 20/20" and "Monday morning quarterbacking." All the choices we make are permanent in one sense, and we all accept this.
If a skydiver has jumped from the plane, he cannot undo that choice. The rest is up to gravity. From the time he leaves the plane to the time he reaches the ground, his choices are very limited. He can't stop off at McDonald's on the way down, for a cheeseburger. That choice is unavailable to him. And if he forgot to strap on his parachute, well… there's no undoing history. He jumped out. That he will fall to the Earth (with or without the aid of a parachute) is simply inevitable. This doesn't violate the concept of Libertarian freedom in the least. Or if someone thinks it does, then they have a distorted understanding of just what Libertarian freedom actually entails.
The skydiver is free to choose to jump from the plane, but he's never free from the consequences of that choice. If his 'chute malfunctions, he can't alter the historical fact that he jumped from the plane. Libertarian freedom doesn't mean that we're free from the consequences of our choices… consequences are the whole reason we make choices to begin with! I choose to go fishing because that choice brings with it consequences: Fun. Peace. Quiet. Satisfaction. These are consequences. If I was free from consequences, why would I choose anything?
During this life, we make our choice: Believe the gospel or continue in unbelief. (there's no neutrality here) When death comes, the effects of that choice become permanent. Those are the rules which God set forth. We are free to choose to believe the gospel or continue to not believe the gospel, but we are never free from the consequences of those choices.
And a third and related point is that if a person understands the gospel properly when they choose to believe it, they understand that the choice they're making has permanent results. They understand that the consequence of choosing to believe the gospel is that they receive everlasting life. Frankly, that's why they choose to believe!! If it wasn't permanent, if their future would remain insecure even after they made the choice, then why bother? For this reason, it makes no sense to say that God takes away my choice once I get to Heaven. The permanence of Heaven doesn't represent a forfeiture of my choice. Rather, it represents God delivering His promise of everlasting life.
Another related challenge is to point out that, apparently, we lose the freedom to sin once we're in Heaven, and so doesn't that represent a loss of freedom?
And here's where we'll launch into another discussion about Libertarian freedom vs. Compatibilist freedom. I have been careful in previous posts not to say that compatibilist freedom is never a reality. With certain qualifications, I'm convinced that Compatibilist freedom is an appropriate way to describe God's freedom and it's an appropriate way to describe our freedom once we're in Heaven.
I'll explain that further in the next post.