It is God who Justifies His Elect !
Rom 8:33
33 Who shall lay any thing to the charge of God's elect? It is God that justifieth.
This fact alone in and of itself is enough to declare all of God's Elect Justified by Him. Whenever the scripture mentions Justification, its restricted to His Elect Isa 45:25
25 In the Lord[Jesus Christ] shall all the seed of Israel[God's Elect] be justified, and shall glory.
Now, since when did God have the will to Justify His Elect ? It was conceived in the Mind of God from Everlasting not to impute or charge sin to those of His Elect. For that must be the case if it was anything of an Everlasting Covenant struck with His Son, on their behalf, and so we have that which is called in scripture " the Blood of the Everlasting Covenant " Heb 13:20
20 Now the God of peace, that brought again from the dead our Lord Jesus, that great shepherd of the sheep, through the blood of the everlasting covenant,
This Covenant will be revealed to all who have a Covenant Interest in it, like David had it revealed to him 2 Sam 23:5
5 Although my house be not so with God; yet he hath made with me an everlasting covenant, ordered in all things, and sure: for this is all my salvation, and all my desire, although he make it not to grow.
Which at least by the Divine Purpose, and according to this Covenant, Christ is the Lamb that had been slain from the foundation Rev 13:8; 1 Pet 1:20, and if so slain, He was slain in the Divine Purpose for the sins of His Elect imputed to Him. In the Divine Purpose Christ had already been made sin[by imputation] for the elect 2 Cor 5:21 that He may in the fulness of time actually be slain for in our time.
So if God purposed to impute their sins to Christ, then when did He not impute them to Him ? See Ps 33:11 And when did He impute their sins to them ?
By this purpose conceived in the Mind of God, not to impute sin to His Elect from everlasting would at the least account for them to be by Him Justified from all their sins [by non imputation] from Everlasting. Paul preached of some being Justified from all things Acts 13:39
39 And by him all that believe are justified from all things, from which ye could not be justified by the law of Moses.
Justified here means to be cleared, absolved ,freed from every charge against them before God's Law and Justice, which could not have been done by the code of moses and the Levitical Priesthood.
So you see here in Acts 13:39 to be justified more so of being set free from sin and it's guilt and penalty, from which the mosaic administration and ts priesthood could not do, however it was done by that once and for all oblation of Christ, and made it count for all whom He died, Justified from all things, as it pertaineth to the things of God and the People Heb 2:17
17 Wherefore in all things it behoved him to be made like unto his brethren, that he might be a merciful and faithful high priest in things pertaining to God, to make reconciliation for the sins of the people.
Again, this reconciliation or justification from all things, was restricted to the sins of the People of the Elect !
And God never charged them with their sins, but charged them to Christ, before the world began !
Now do not misunderstand, they were charged with sin, but those charges never were laid or imputed to them, but to Christ. The charges were real and Christ bore a real punishment for them.5