17 Learn to do well.
Seek justice.
Relieve the oppressed.
Judge the fatherless.
Plead for the widow.” 18 “Come now, and let us reason together,” says Yahweh:
“Though your sins be as scarlet, they shall be as white as snow.
Though they be red like crimson, they shall be as wool. 19 If you are willing and obedient,
you shall eat the good of the land; 20 but if you refuse and rebel, you shall be devoured with the sword;
for the mouth of Yahweh has spoken it.”

The Judgment and Redemption of Zion

21 How the faithful city has become a prostitute!
She was full of justice; righteousness lodged in her,
but now murderers. 22 Your silver has become dross,
your wine mixed with water. 23 Your princes are rebellious, and companions of thieves.
Everyone loves bribes, and follows after rewards.
They don’t judge the fatherless,
neither does the cause of the widow come to them.

Matthew Henry's Commentary on Isaiah 1:17-23

Commentary on Isaiah 1:16-20

(Read Isaiah 1:16-20)

Not only feel sorrow for the sin committed, but break off the practice. We must be doing, not stand idle. We must be doing the good the Lord our God requires. It is plain that the sacrifices of the law could not atone, even for outward national crimes. But, blessed be God, there is a Fountain opened, in which sinners of every age and rank may be cleansed. Though our sins have been as scarlet and crimson, a deep dye, a double dye, first in the wool of original corruption, and afterwards in the many threads of actual transgression; though we have often dipped into sin, by many backslidings; yet pardoning mercy will take out the stain, Psalm 51:7. They should have all the happiness and comfort they could desire. Life and death, good and evil, are set before us. O Lord, incline all of us to live to thy glory.

Commentary on Isaiah 1:21-31

(Read Isaiah 1:21-31)

Neither holy cities nor royal ones are faithful to their trust, if religion does not dwell in them. Dross may shine like silver, and the wine that is mixed with water may still have the colour of wine. Those have a great deal to answer for, who do not help the oppressed, but oppress them. Men may do much by outward restraints; but only God works effectually by the influences of his Spirit, as a Spirit of Judgment. Sin is the worst captivity, the worst slavery. The redemption of the spiritual Zion, by the righteousness and death of Christ, and by his powerful grace, most fully accord with what is here meant. Utter ruin is threatened. The Jews should become as a tree when blasted by heat; as a garden without water, which in those hot countries would soon be burned up. Thus shall they be that trust in idols, or in an arm of flesh. Even the strong man shall be as tow; not only soon broken, and pulled to pieces, but easily catching fire. When the sinner has made himself as tow and stubble, and God makes himself as a consuming fire, what can prevent the utter ruin of the sinner?