I'm considering going back to the Orthodox faith(cradleOrthodox) and have had some lenghtly conversations with the priest. He recommended the book called The Law of God. In it it says this:
"As the vanquisher of death, Who arose on the third day, He saved us also from eternal death. He will resurrect all of us, all the dead, when the last day of the world comes; He will resurrect us for joyful, eternal life with God"
Does that mean we are basically asleep in the ground until Christ comes? What about our family? Will we not see those that die until last day of the world?
I'll be honest, this scares me...
It's okay, that isn't what it means. When we repose, our souls separate from our bodies and ascend to heaven. Before Christ's descent to hades and his resurrection, the souls of the dead would go to "hades" (different than hell) and were there awaiting Christ to come free them. Now the souls proceed immediately to a "foretaste" of what we will/might experience at the Final Judgement.
It is largely unknown exactly what happens, but I will give you feed back on what I've been taught. (this may not be EXACTLY what happens, keep that in mind)
Essentially this is what happens (or so I've been told)...
Our soul departs from our body, at this time, the soul is "uncomfortable" (for lack of a better word) and must learn to exist without the body for a time. The soul has no more restrictions on it and we suddenly find ourselves naked, all our deeds and the depths of our soul are visible for all to see. We immediately proceed to a "foretaste" of what we might experience in the end. This foretaste, however, is not final.
The reason is this: During life, because we are sinful, we build up "barriers" towards God and towards other people. All of these "barriers" (what we call sin) prevent God's grace from entering in (whether its from God or others). Our goal in life is to cure ourselves from sin and it's spiritual effects. Essentially, we are to work in this life to break those barriers down and return our soul to it's rightful place (that is, in control of the body, not the other way around). We are to become "Christ-like" and "God-like", we can never be equal to God, but this process is also called "deification". We were all created to be like God (though never equal to him) and because of our fall, we have tainted this image. Our goal is to break down the barriers, resist sin, receive and give grace, retain control of our bodies etc... (seems like a tall order huh?)
However, if in life, we do not accomplish this on our own, we are not finished when we die. When our soul separates from our body, it's work continues and it learns to live without the body (so that it can be in control of it eventually), during this time, we can do nothing on our own to improve our state. However, through prayers/intercessions of the Saints and of those still alive, our state can be improved and our barriers can be broken down further. (this doesn't guarantee salvation though)
Eventually, when the Last Day comes, the Lord will resurrect EVERYONE, their bodies will be resurrected and restored, and their souls will be reunited with their bodies. The judgement will occur, and this is when God reveals his entire grace. Those who refuse to accept it and who have become hardened against God will be consumed (burn) by God's grace, but those who fully accept it and who have worked hard and kept the faith, they will be illumined by his grace.
Now I would like to talk about "universal salvation". This is the belief that ALL will eventually be saved. This was condemned as heresy. We can certainly hope and pray that everyone might be saved, but we cannot say that everyone will be saved. We even might pray for Satan and his salvation, but this isn't commonplace. Because our prayers do indeed help others, even those who are dead, it would be right and necessary for us to pray for even the humans that caused the most harm to others like Hitler and Stalin. These two men still have a chance, but it is up to us and the Saints to pray for them. (but in the end, it is still up to them and the state of their soul)
Lastly as a disclaimer, this exact belief may not be completely universal, and may just be theologoumena (like a personal opinion, not dogma). Also, this may not be understood completely literally, we shouldn't think of this as a play-by-play of what happens, we don't know what happens nor what will happen, but we have a vague idea.
What we are required to believe though, is this:
"... from thence he (Christ) shall come again, with glory, to judge the quick and the dead;
whose kingdom shall have no end. ... we look for the resurrection of the dead, and the life of the world to come. Amen." - From the Nicene Creed
To answer your question in short, the resurrection of the dead is resurrection of the body, our souls don't sleep until the end, our souls are active in heaven (or "hell", if you want to call it that) until the final day of judgement when they are reunited with the body and then judged.