Romans 3:20 Therefore by the deeds of the law there shall no flesh be justified in his sight: for by the law is the knowledge of sin.
I take interest in this verse to stress a point about being justified that must be understood. We read in the above verse the phrase justified in His sight. Justification is in the eyes of God. To be just before God is a declaration. It is to say that a sinner stands before God in a just manner. It is to be right with God. It is to be declared righteous before the holy God. It is not an infusion of righteousness, but is a declaration of righteousness. You might say well how then does that not make me righteous? Tell me the first day, or even the first hour that you do not sin. We are not righteous beings, but we are declared by God to be righteous. Look at what Paul says in Romans 7:
Romans 7:18 For I know that in me (that is, in my flesh,) dwelleth no good thing: for to will is present with me; but how to perform that which is good I find not. 19 For the good that I would I do not: but the evil which I would not, that I do.
Though the risen savior had spoken to Paul, had taught him for 3 years, though he wrote almost half of the entire New Testament, Paul could see the sin within himself. He was not a physically righteous man, but he was declared by God to be so.
To be justified is to be declared righteous before God in connection with the cross of Christ. We will come to see that we are declared righteous because our representative was righteous Himself. God cannot say that we are righteous, but He can say the one who died for us is. We are in the sight of God seen just as righteous as Jesus Christ our Savior. We are legally, based upon the satisfaction of the law of God, declared to be justified. We are found not only not guilty, but we are declared to be righteous in the eyes of God.