"Come now, and let us reason together, saith the LORD: though your sins be as scarlet, they shall be as white as snow; though they be red like crimson, they shall be as wool."
These last two commands emphasize the redemptive love of God. God tenderly calls for His people to come, and to come immediately. God has given mankind something which He has not given to any beast - the ability to reason. The Lord wants man to consider his present course, his past and his future. Just like most people of today, many of Israel's population were content to live in the here and now, not considering the far reaching consequences of a failure to honestly seek God. God gave man the ability to reason. Human reason is a great privilege, but it has dire consequences if not used to follow after God's commandments.
God promised Israel spiritual cleansing if they would hear. Salvation comes not by religious ritual or rule-keeping. It comes only through faith in the righteousness of God. When God saves a man's soul, nothing is left to chance. Israel's sins were many and very vile. They had been guilty of child sacrifice, idolatry, perversion, oppression, drunkenness and much, much more, yet God promised a full cleansing to the sinner who would turn around and flee to God's saving grace.
"If ye be willing and obedient, ye shall eat the good of the land: But if ye refuse and rebel, ye shall be devoured with the sword: for the mouth of the LORD hath spoken it."
It was not enough for Israel to simply acknowledge their disregard for God's Law; they needed to demonstrate a change of heart through obedience. God's grace is sufficient to cleanse the sinner, but it is not intended to enable the continuance of an unbiblical lifestyle. God called Israel to obedience, and today He is calling lost men of every nation to obedience.
Now to him that is of power to stablish you according to my gospel, and the preaching of Jesus Christ, according to the revelation of the mystery, which was kept secret since the world began, but now is made manifest, and by the scriptures of the prophets, according to the commandment of the everlasting God, made known to all nations for the obedience of faith: (Romans 16:25-26)
If Israel would change their ways, they would enjoy the physical prosperity of God's blessings upon the land. This promise is to Israel and not to the Church. The two must never be confused; otherwise, serious doctrinal error will occur. However, the principle of this promise may safely be applied in any dispensation. Obedience always brings spiritual prosperity; and, in many instances, physical prosperity. Many professing believers are not at peace in their souls because they are attempting to remain loyal to the world when God has called them unto obedience to His holy character.
The LORD offered Israel an alternative. They could choose rebellion, but it would come at a great price. God does not respect persons. The same rules apply to everyone. Unholy living comes with an expensive pricetag.
The LORD did not provide His people with a third option. Man's heart is deceptive. Many people believe that they will be able to harbor some rebellion and still enjoy God's blessings. The Bible presents no such alternative.