Faithful is a marriage term. It is in reference to the faithful wife, and in this verse, a faithful wife who has become unfaithful.
In the Old Testament, the nation of Israel was referred to as a wife, bound to God through the various Levitical laws. A relationship that was destined to failure.
In the New Testament the people of God, believers, are referred to as a bride in preparation for the ultimate wedding. The new binding or marriage contract, is by means of the work of Christ, which is a permanent binding and union between God and believers.
The harlot is the unfaithfulness of the wife, believers, through sin and works (human good). From asceticism to lasciviousness, and everything in between where people pursue everything but truth, in their relationship with God.
All acts of sin, and crime and self-righteousness and so forth, are unfaithful activities of believers toward God. They are no better than the actions of a prostitute.
Where once the city, or the faithful wife, was filled with truth and doctrine, and now is filled with lies and deceit and rottenness. The city of Jerusalem means City of Peace, and that peace is due to the actions of doctrine resident in the soul of the mature believer.
But now that the faithful believer has turned away from God, and has pursued or taken up with the filth of the world, now the city is likened to the home of prostitution.
Judgment is a reference to justice and righteousness. Lodged in it, means that the doctrines and truth of God were once lodged, resident, a place of dwelling, and home.
Therefore, doctrine once resided in Jerusalem. Doctrine once resided in its citizens. Spiritual maturity once occupied the lives of those who were faithful believers in the Son of God, the Messiah, the Christ, the Savior, Jesus Christ.
But now the believers have turned away, have faded in their faith, have become murderers. And murderers means to have become unjust judges, people who have forgotten truth, people who have become indifferent toward others, people who have become selfish and greedy, people who take what they wish, at the expense and loss of others.
The home of the spiritually mature, has been replaced with the home of filth and degeneracy. And the next few verses explain just how that has occurred.