Justification is essentially a legal decision, as it is written:
Deuteronomy 25:1If there be a controversy between men, and they come unto judgment, that the judges may judge them; then they shall justify the righteous, and condemn the wicked.
And from a negative perspective:
Proverbs 17:15He that justifieth the wicked, and he that condemneth the just, even they both are abomination to the LORD.
Lest anyone should say that this only goes for human judges, it is also written:
1 Kings 8:32Then hear thou in heaven, and do, and judge thy servants, condemning the wicked, to bring his way upon his head; and justifying the righteous, to give him according to his righteousness.
It is the law that condemns, in that Adam and we have sinned. This is exemplified when it is written,
2 Corinthians 3:9For if the ministration of condemnation be glory, much more doth the ministration of righteousness exceed in glory.
But there is a way for us to avoid this condemnation, as it is written,
John 5:24Verily, verily, I say unto you, He that heareth my word, and believeth on him that sent me, hath everlasting life, and shall not come into condemnation; but is passed from death unto life.
Moreover, it is written,
Romans 8:1There is therefore now no condemnation to them which are in Christ Jesus, who walk not after the flesh, but after the Spirit.
Therefore we may be bold and thankful, for we are no longer condemned, as it is written,
Romans 8:34Who is he that condemneth? It is Christ that died, yea rather, that is risen again, who is even at the right hand of God, who also maketh intercession for us.
But of course this last verse indicates that there are those who will condemn us before the judgment day when we will finally be fully justified before the Most High Judge of all the earth.