Dear Conrad - Jesus died for our sins, right? Right. So what about all of the God-following people in the Old Testament? If the only way to Heaven is through Christ and Christ didn't come and die for their sins yet where did their souls go? Is the answer also applicable to people nowadays who have no access (for whatever physical/location reasons) to Christ?? - Jane Uncommon
Dear Jane Uncommon,
This is an excellent question. Christ is all through out the Old Testament (as early as Genesis 3:15) in the promise of the Messiah. So the Old Testament people still had to put their faith in God. Having faith in God also means having faith in his promises - and his promises included The Christ (which means “Messiah”).
As far as where their souls went…
It’s the same as us today.
I’ll clear up one common misconception. When believers die, they do not go to the final heaven that’s going to be around forever and ever. There will be a new heaven and new earth (Rev 21:1).
We still need to be resurrected. 1 Thess 4:16 says, “For the Lord himself will come down from heaven, with a loud command, with the voice of the archangel and with the trumpet call of God, and the dead in Christ will rise first.” 1CO 15:42 says, “So will it be with the resurrection of the dead. The body that is sown is perishable, it is raised imperishable; [43] it is sown in dishonor, it is raised in glory; it is sown in weakness, it is raised in power; [44] it is sown a natural body, it is raised a spiritual body.”
All this meaning that there is some sort of existence between our death and resurrection.
The only description of this place is in one of Christ’s parables LK 16:22 "The time came when the beggar died and the angels carried him to Abraham's side. The rich man also died and was buried. [23] In hell, where he was in torment, he looked up and saw Abraham far away, with Lazarus by his side. [24] So he called to him, `Father Abraham, have pity on me and send Lazarus to dip the tip of his finger in water and cool my tongue, because I am in agony in this fire.' LK 16:25 "But Abraham replied, `Son, remember that in your lifetime you received your good things, while Lazarus received bad things, but now he is comforted here and you are in agony. [26] And besides all this, between us and you a great chasm has been fixed, so that those who want to go from here to you cannot, nor can anyone cross over from there to us.'"
Many refer to this intermediate existence/place at “Abraham’s Side” or "Abraham's bosom". And this place is still in the presence of God - in some existence without our resurrected bodies. After we are resurrected, with spiritual bodies, at the end of the world, then we will stand before God and enter into the new heaven.
(And to answer the second part of your question. No, this answer is not really applicable to those who have not heard the gospel. That question needs it's own line of answers.)