In theology, what covers sanctification, and glorification? Is it all in soteriology?
And how does one make a difference between justification and sanctification?
There are 3 stages of sanctification, some say 4 but that concerns the Perfect Age when time is no more with no sin left in the universe. I'll leave this one out, I don't feel it's relevant to the discussion.
The stages are,
Positional Sanctification
Progressive Sanctification
Glorified Sanctification
When one comes to Christ in faith accepting Him as Saviour, that person is justified by God. He is no longer a law-breaker, he is a law-keeper in the eyes of God. God only accepts us on behalf of Christ. This is our Position in Christ, we are now in the family of God. Our Position in Christ is based completely on our faith in what Christ has done for us.
Now that we are in the family of God, we are treated as the Children of God. We have been found not guilty (justified) before God in Christ, which means we have been set apart (sanctified) in Christ. This is the first stage of sanctification, our Position in Christ, in the family of God, set apart from the world to His will.
You have now been called by God, accepted His call, and now positioned in Christ. The Holy Spirit now begins the process of conforming you into the likeness of Christ. This is the second stage of sanctification. This process continues the entirety of your life here on earth. You are being refined throughout your life, becoming more in the likeness of Christ. It's the continuing Progressive sanctification by the Holy Spirit.
All the children of God who have passed before us, from the time of Adam until this very moment, are awaiting the resurrection. This is when the believer both dead and still alive will be changed, "in a moment, in the twinkling of an eye." This is when death is swallowed up in victory, the mortal becomes immortal. This is the third stage of sanctification, we will receive gloried bodies as Christ received at His resurrection from the dead. At this point we can no longer sin, we have become perfect in Christ.
It is our faith in the risen Saviour that has brought us to this point. We have done nothing, nor could we do anything to deserve it. It is a free gift from God through faith in His Son.