I think justification is an under-appreciated doctrine, and that's partly because it has been cut off from Jesus.
Justification is not just being forgiven and having the slate wiped clean. It is not only 'just-as-if-I've-never-sinned', but it is also not 'just-as-if-I-had-lived-a-perfect-life'. Actually, its 'just-as-if-I-was-Jesus'.
Among other things, this means that justification is not a necessary step to being adopted as sons. In fact, I may be as bold to say that justification = adoption.
Jesus was justified by God in his resurrection from the dead (Rom 4:25; 1 Tim 3:16). The Jews, and God the Father through them, declared him a sinner. God the Father by the Spirit then raised him from the dead, overturning their verdict and declaring him righteous (Acts 2:3-24).
But in the covenantal context righteousness is not just doing good according to the natural law (although it is not less than that), it is being the people God called Israel to be - and God called Israel to be his son (Ex 4:22; Rom 9:4). Sadly, instead they acted like sons of Satan and crucified the one who not only called God Father, but by his life showed himself to be God's only Son. So, when God the Father raised Jesus from the dead he declared him to be the Son of God in power (Rom 1:4).
If we are united in Christ by Baptism in faith then that same declaration of God the Father over Jesus as he came out of his water-Baptism 'grave' and his blood-Baptism grave is declared over us as well (Matt 3:17). We are sons in whom the Father is well pleased!
So, don't downplay justification, or teach it reductionistically, but celebrate it in all it's riches!
