Justification is when God the Father accepts us as righteous through the work of Christ and the Holy Spirit in us. Justification precedes sanctification and glorification. As far as I know, it must be provided to us by God’s grace before we leave planet Earth.
Justification appears to have the characteristic of a “legal fiction.” We are never totally righteous until we are finally glorified in heaven but we are treated as such on earth because our glorification is a sure thing. I believe that once justification is granted to us, it will never be taken away. One reason for this is that justification does not come from us nor is it given for what we are or think or for what we do.
By his sinless life and total obedience to his Father’s will, Jesus made it possible, I believe, for the Father, in justice, to provide righteousness to those who are effectually called.