On God's side of this matter all the work necessary to
make both our justification and our sanctification effective and complete has already been done by Christ (Rom 3:28). Both are given, and given only, to the believer who accepts the work of Christ on his behalf (Gal. 2:16; Acts 26:15, 18).
To "justify" in the Scriptural sense is not to make
a man righteous because of his own actions, but to reckon to him a Righteousness worked out by another for him. The one so justified is regarded as if he had never sinned. To use the Scripture expression, Righteousness is imputed to him (Rom. 4:6).
No man can be justified before God by his own works (Rom. 3: 20). Those who trust in Christ are justified by His Blood - His Blood
being His Life given when He died on the Cross (Lev. 17:11; Col. 1:20; Rom. 3:21, 22, 26; 5:9).
The righteousness reckoned to the believer is the righteousness of the life of Christ Himself as Son of God (11 Cor. 5:2 1), so perfect and complete that it is called in the Scriptures the righteousness of God (Rom. 3:22).
Christ was raised from the Dead for our justification, and by this we know that His Death for our sins has completely satisfied the demands of Divine Righteousness. Thus we have the assurance of our justification (Rom. 4:25).
(From Fundamentals of the Apostolic Church, p 15)