John Owen says Christians need to “be killing sin, or it will be killing you.” Yet from my experience most Christians aren’t employing everything they have at their disposal to kill sin or to pursue sanctification in any regard. The most I hear about this is the throwaway line, “I’m struggling with X sin” but upon further questioning often those who say this aren’t struggling at all with a sin; they’ve often simply identified that they have a persistent sin, and yet do nothing about it.
Then when I reflect on my own fight with sin, I’m ashamed to realise I too often fall into the same trap of identifying sin without fighting it. I started to consider why this is the case for me. Why is it that I know about my sins, but I don’t fight them? And I have come to the conclusion that I (and I suspect many others) don’t fight sin because I don’t know what my role is in sanctification.
In order to figure it out I had to understand three things:
- God’s sovereignty and human responsibility are friends concerning progressive sanctification, not enemies needing reconciling.
The Bible says that God is the one who sanctifies us completely (1 Thess 5:23) and at the same time it commands the Christian to perform the particular actions of sanctification, such as the putting to death of sin and the living out of the resurrected life (Col 3:5,12) and not only does it command us to do this, it also holds us to account for it, as seen in Hebrews 12:14 which says:
“Strive for peace with everyone, and for the holiness without which no one will see the Lord.”
If God is the one who completely sanctifies us, why are we commanded to pursue sanctification, let alone be held responsible for sanctification? Is God responsible for our progressive sanctification or are we responsible for our sanctification?
I wasn’t the first person to ask this question. Someone once asked Spurgeon if he could reconcile God’s sovereignty and human responsibility – to which he answered, “I wouldn’t try, I never reconcile friends”. 
Spurgeon’s answer challenges the assumption behind the question. The assumption is that these truths aren’t compatible. But the Bible doesn’t view them as incompatible; in fact the Bible assumes the opposite. Jerry Bridges helpfully paraphrases John Owen in showing the relationship between the two:
“Our duty and God’s grace are nowhere opposed in the matter of sanctification; for the one absolutely supposes the other. We cannot perform our duty without the grace of God; nor does God give His grace for any other purpose than that we may perform our duty.” 
The Bible doesn’t see God’s sovereign hand over progressive sanctification as something in opposition to our active participation. It sees the dependence of each one on the other. Take for example Philippians 2:12-13 or Ephesians 2:10:
Phil 2:12-13 Therefore, my beloved, as you have always obeyed, so now, not only as in my presence but much more in my absence, work out your own salvation with fear and trembling, for it is God who works in you, both to will and to work for his good pleasure.
Eph 2:10 For we are his workmanship, created in Christ Jesus for good works, which God prepared beforehand, that we should walk in them.
Both these passages display our duty and God’s grace as going hand in hand in progressive sanctification.
In Philippians 2 we are to work out our salvation… for it is God who works in us, and in Ephesians 2 God’s sovereign grace provides what is necessary for our duty and our duty is the desired end of God’s grace.
God’s sovereignty and human responsibility regarding sanctification are not presented in the Scriptures as enemies needing reconciliation, but as friends.
So what does this friendship look like? In
Part 2, we will see how this operates in the life of the Christian.
 John Owen, Mortification of Sin: Dealing with Sin in Your Life. (Tain, United Kingdom: Christian Focus Publications, 2012), 27.
 This article is dealing with progressive sanctification, not positional sanctification. Positional sanctification is the peculiar dedication, consecration, or separation” of persons or things “unto the service of God by His own appointment.” Progressive sanctification concerns the “real and internal” sanctification which communicates the principle of holiness “unto our natures, attended with its exercise in acts of duties of holy obedience unto God.” John Owen and William Goold, The Works of John Owen. (London: Banner of Truth Trust, [1865-68], 1965), vol. III, Book IV, Ch 1, 370.
 J I Packer, Evangelism and the Sovereignty of God. (Nottingham, United Kingdom: Inter-Varsity Press, 2010), 43.
 Bridges paraphrasing Owen, Jerry Bridges, The Discipline of Grace : God’s Role and Our Role in the Pursuit of Holiness. (Colorado Springs, Colo. : NavPress, 1994., 1994),133.