(Image courtesy of https://image.desiringgod.org.)

God possesses a sinless nature.  Therefore, He is ruled by righteousness, holiness, and perfection.  It is impossible for God to sin.

Man, on the other hand, possess a sinful nature.  Therefore, he is ruled by sin and mastered by it.  The wages of such slavery is death and eternal condemnation.

Even after regeneration, man still possesses a sin-nature, though we are no longer slaves to it - for Christ has set us free!  After conversion, the old man (the sin nature) is dead, as in we are no longer mastered by it; but we are not free from even this dead man while we still live on this earth.  No; we still struggle against sin (the old man), though the Spirit (the new man) is slowly but steadily ruling and reigning in our lives by the power of God.  Though we have been given a new name and a new life through the sinless, perfect sacrifice of Jesus Christ at conversion, we still sin.  This is, perhaps, the area of greatest concern for Christians: why do I keep sinning and am I a bad Christian for sinning?  You keep sinning because you have a sin-nature, and your sinning even as a Christian reveals that God-hating nature within you.

And this is why it is the grace of God that saves you and nothing else.  It is the grace of God that remains faithful to His people even when His people wander away from Him.  It is the grace of the Good Shepherd that does not lose one sheep, but goes in search of the one who wanders away and brings him back to His fold.  It is the grace of the Good Shepherd that disciplines us when we go astray and directs us back to the path of righteousness.  It is the grace of the Holy Spirit that wars against the sin-nature, transforming us slowly but surely into the image of Jesus Christ, the Sinless One.

It is the sin-nature that condemns each one of us; it is the grace of God that saves all who repent.

Everything inside my sinful nature hates God.  Even as a Christian for over twenty years, my sin-nature, though I am no longer controlled by it, is still God-hating.  When I am being prodded by the Holy Spirit to pray, my sin-nature speaks up and says, "You don't need to talk to God.  You can do this yourself."  I hate God in my flesh and I long to do the things that my sin-nature desires.  Yet it is God, in His grace, that disciplines me and corrects me and rebukes me and reproves me - convicting me of my sin which is always before me and bringing me to repentance, which the grace of God will receive as a true act of worship and turn into my joy which will result in His glory.  One man put it this way: "The life of a Christian is one of continual repentance."

Concerning the grace of God, the New Testament letters speak of some who falsely stated, "Well then, since it depends not on us but on God's grace, why don't we just do whatever we want - just keep sinning and let God's grace increase toward us!"  Of course, this is false teaching, for those who have tasted the conviction of God caused by their sins, and then received His irresistible grace leading to repentance, desire no longer the works of the flesh, but now war with them - the spirit versus the flesh.  The truly repentant believer, being constantly conformed unto life through the grace of God in Jesus Christ given through the Spirit, grows increasingly hostile toward the sin-nature, waging war against the dead, old man, becoming more alive day-by-day in the presence of God.

The faithfulness of God to His people and the learned responsibility of humans toward God is summed up best by Charles Spurgeon, who said, "There are two laws at work: God's sovereignty and man's responsibility, which converge at some point in eternity."  God initiates the work of salvation in the life of the God-hater and convicts us through His righteousness and holiness - through His perfect nature.  Then it is man who feels the weight of such conviction and repents.  It is the surrendering of man's will unto God's and the molding of God in our wills that leads to eternal life.

Therefore, I will praise all the more gladly and joyfully the grace of our Lord Jesus Christ, who is at work within my members of sin, transforming, molding, regenerating, and conforming - until I am complete in the day of glory and will be revealed before my Father without fault and with great joy by my Savior, Jesus Christ.

"Prone to wander, Lord I feel it,
Prone to the leave the God I love,
Here's my heart, Lord, take and seal it,
Seal it for Thy courts above" (Come Thou Fount of Every Blessing).