(Image courtesy of http://therebelution.com.)
"Wash yourselves; make yourselves clean; remove the evil of your deeds from before My eyes; cease to do evil, learn to do good; seek justice, correct oppression; bring justice to the fatherless, plead the widow's cause.  Come now, let us reason together, says the LORD: though your sins are like scarlet, they shall be as white as snow; though they are red like crimson, they shall become like wool.  If you are willing and obedient, you shall eat the good of the land; but if you refuse and rebel, you shall be eaten by the sword; for the mouth f the LORD has spoken" (Isaiah 1:16-20). 
"Whoever has My commandments and keeps them, He it is who loves Me.  And he who loves Me will be loved by My Father, and I will love him and manifest Myself to him" (John 14:21). 
"Owe nothing to anyone except to love one another; for he who loves his neighbor has fulfilled the law.  For this, 'You shall not commit adultery, you shall not murder, you shall not steal, you shall not covet,' and if there is any other commandment, it is summed up in this saying, 'You shall love your neighbor as yourself.'  Love does no wrong to a neighbor; love therefore is the fulfillment of the law" (Romans 13:8-10).

The third question of the Westminster shorter catechism is this: "What do the Scriptures principally teach?"  Answer: "The Scriptures principally teach what man is to believe concerning God and what duty God requires of man."  Indeed, this is what the Bible most clearly teaches: who God is and what man must do to please God.

There is but one duty that God requires of man: obedience, that is, adherence to the whole and entire counsel of God.  The first man and woman, however, failed to obey God.  They rebelled and sinned against Him.  Therefore, we have all suffered their fate of death and judgement.  The demand for obedience is still present, though, in order to live: "But this command I gave them: 'Obey my voice, and I will be your God, and you shall be my people. And walk in all the way that I command you, that it may be well with you'" (Jeremiah 7:23).

Obedience, then, is the way to life.  Any hint of disobedience is rebellion, and any good king knows that rebels must be punished.  The answer, then, is simple: rebels should obey the King again.

There is but one problem: man is incapable of obedience, and even if he was capable and began to obey completely and fully right now, all his past wrongs must be accounted for and justly punished.  As it is, "None is righteous, no, not one; no one understands; no one seeks for God.  All have turned aside; together they have become worthless; no one does good, not even one" (Romans 3:10-12).  As a result, man remains a rebel and will most assuredly be punished because the King is good.

Has the Lord, then, commanded us to obey in mockery?  Has He heaped rules on us, knowing full well that no one could keep them, just to watch us suffer and die under them?  On the contrary, "the Law of the Lord is good" and "it is a light unto my path" (Psalm 19 and 119).  Never are the commands of God evil.

Rest assured, our problem has been solved by the Lord, for He has done for us what we could not: He has provided atonement for rebels in the person of Jesus Christ!  This is what the prophets and the law all pointed toward: a perfect substitute!  Jesus Christ lived the life of perfect obedience that no man could live.  Since He, then, fulfilled all obedience in His life, His death was purposeful and satisfactory for all rebels who would trust in Him for their righteousness.  Through a great exchange, God has imputed Christ's perfect obedience upon rebels; that is, any who repent of their rebellion and trust in Christ!  Their accounts have been wiped clean of all past, present, and future rebellion!  Notice this does not mean we will never be rebellious again, but that it will not count against us.

Shall we go on sinning then, if it doesn't count against God's elect?  By no means!  For submission to the grace and love of Christ produces in us love beyond reckoning.  We grow in love for our Lord, who has done this great thing out of His own grace and love, not because we were deserving of it or even that we were lovable.  God gave His Son as our substitute out of His own good pleasure, loving-kindness, and grace.

This same love, then, that has saved us, is what we ought to grow into - even the perfect love of God in Christ Jesus.  For Paul says in Romans 13 that all the commandments of God are fulfilled in love, and we ought to keep all the commandments of the King.  For in love do we rightly treat others, and in love and desirous affection do we respond to the grace of God.  Love is the obedience produced by faith, for "whoever does not love does not know God" (1 John 4:8).

Oh, the simple joy of knowing God in Christ!  Oh, the simple exchange He has made for rebels!  Oh, the love and grace of God in Christ!  Oh, the simple Gospel!  How foolish the Lord must have been to exchange His perfect Son for sinful rebels; how difficult it is for the wisdom of man to understand the foolishness of God (1 Corinthians 3).

"If you obey the commandments of the LORD your God that I command you today, by loving the LORD your God, by walking in his ways, and by keeping his commandments and his statutes and his rules, then you shall live and multiply, and the LORD your God will bless you in the land that you are entering to take possession of it" (Deuteronomy 30:16).