Isa 1:21 How is the faithful city become an harlot! it was full of judgment; righteousness lodged in it; but now murderers.
The faithful city was Jerusalem, the place of worship and the temple of God had turned to sin and rebellion; worshipping other gods.
Isa 1:22 Thy silver is become dross, thy wine mixed with water:
Silver is become dross, worthless, being used for worthless things; it was not used to help the poor or those in need, The wine weakened with water, wine was no longer pure but diluted.
Isa 1:23 Thy princes are rebellious, and companions of thieves: every one loveth gifts, and followeth after rewards: they judge not the fatherless, neither doth the cause of the widow come unto them.
The princes are as corrupt politicians, rebellious, giving away the country to thieves: everyone loving gifts and bribes: they only help those who will help them. Righteous judgment had left them. They may claim to care for others only to stay in power. This was supposed to be the city of God, but it had become the city of thieves and corruption.
Jesus came to restore righteousness and to heal the sick, even in Jerusalem.
Mat 21:11 And the multitude said, This is Jesus the prophet of Nazareth of Galilee.
Mat 21:12 And Jesus went into the temple of God, and cast out all them that sold and bought in the temple, and overthrew the tables of the moneychangers, and the seats of them that sold doves,
Mat 21:13 And said unto them, It is written, My house shall be called the house of prayer; but ye have made it a den of thieves.
Mat 21:14 And the blind and the lame came to him in the temple; and he healed them.
James 1:26 If any man among you seem to be religious, and bridleth not his tongue, but deceiveth his own heart, this man's religion is vain.
James 1:27 Pure religion and undefiled before God and the Father is this, To visit the fatherless and widows in their affliction, and to keep himself unspotted from the world.
Jerusalem in Isaiah's time had fallen into sin. In this time the city leaders in Jerusalem were to host a homosexual invasion, little has changed in Jerusalem.
Jesus will return and Jerusalem again will be the place of righteousness.
Rom 11:25 For I would not, brethren, that ye should be ignorant of this mystery, lest ye should be wise in your own conceits; that blindness in part is happened to Israel, until the fulness of the Gentiles be come in.
Rom 11:26 And so all Israel shall be saved: as it is written, There shall come out of Sion the Deliverer, and shall turn away ungodliness from Jacob:
Rom 11:27 For this is my covenant unto them, when I shall take away their sins.