Apologies for this being a long post, but it is a complicated issue within Nazarenedom.
I would strongly agree with his basic premise, that "sin," defined as sinful acts, is not what sends people to hell. I have said the same thing many times across the years, especially in the context of a rather moralistic version of the holiness movement in which I grew up. The only "sin" that separates us from God is our own rejection of God and his Lordship over our lives. I would talk about that in different terms than Keller; I would not say it is just "self-righteousness" or trying to save ourselves. That is a little too cerebral and too passive for me. I think the sin that separates us from God is the final practice of self-centeredness, in which in some particular way (or many ways) we very actively place our own wants, desire, and interests above God. The danger is that such attitudes and acts can take many forms. Keller hinted at that when he pointed out the difference between adultery (something quite obvious) and greed (something far more attitudinal and personal, yet comes out in actions). Jesus made the same point in the Sermon on the Mount.
That simply means that most anything in our lives can become an occasion for rejecting God. God is patient and by his grace constantly calls us to move beyond our self-centeredness, to truly love God and out of that to love others. But if we continue to resist God's call to move beyond where we are, we can finally place a seemingly innocuous action (greed, gossip, arrogance, self-righteousness, bigotry, being judgmental, yelling at other drivers in traffic, etc.) compared to the "big" sins (murder, theft, adultery, etc.) ahead of God. In doing so, by our actions, not the specific committing of a specific sin but by the continued willful rejection of God's Lordship over our lives, we say "no" to God.
That is the sin that separates us from God.
Here is where our definitions of sin become important and the concept of growth in grace is crucial. Without taking the time to detail it all, two issues are important. First, Christians sin. Not every day in word thought and deed. And not inevitably in terms of willfully disobeying God. But Christians are not perfect at any stage, and are considerably less so at the beginning of their Christian journey. (One of the biggest mistakes of the holiness movement was equating an instantaneous commitment and experience with perfection of action and attitude.)
We make mistakes. We do things that cause hurt and harm to others. We do things that we know are not the best thing to do. Sometimes we do things knowing it is not within God's purpose. We do not always do what we should do or could do. But sin does not directly equal hell. That is the nature of grace (the theological message of the Noah story). But we must deal with our failures. This is why confessional prayers are so crucial to healthy spiritual growth, if we understand "sin" as those things we do that are not pleasing to God rather than the "sin" that separates us from God:
Merciful God, we confess to you now that we have sinned. We confess the sins that no one knows and the sins that everyone knows. We confess the sins that are a burden to us and the sins that do not bother us because we have grown used to them. We confess our sins as a church. We have not loved one another as Christ loved us. We have not forgiven one another as we have been forgiven. We have not given ourselves in love and service for the world as Christ gave himself for us.
Father, forgive us. Send the Holy Spirit to us, that he may give us power to live as by your mercy, you have called us to live. Through Jesus Christ our Lord. Amen. [A Presbyterian prayer]
Second, as David said so well, sin cannot be the "norm" for Christians. I thoroughly reject the notion that Christians sin every day in word, thought, and deed. That confuses what sin is. And I reject the notion that relationship with God does not change who we are, that salvation is only a legal transaction that pardons our continual sinning while leaving us the same. I am firmly convinced that relationship with God is transformational, which is why Paul uses the metaphor of "new creation."
If we take growth in grace seriously, two things emerge. First, people are at different stages of spiritual growth no matter how many crises they have had. Some Christians do things and practice things that other people do not, and cannot. We can legitimately call some of these sinful without consigning people to hell for it (recall, I labeled actions by some here on NazNet as sinful, without suggesting they are going to hell).
Second, the idea of growth implies that we are not what we used to be and yet are not what we will be. That calls for a huge dose of humility in how we relate to others (of course, we all always assume that we are much further along the road to spiritual maturity than we really are!). I recall something about specks and beams.
Finally, I agree with Keller, as I said in the original post, that our task is to treat people with the love of Christ, and with personal respect, no matter where they are. It is not my task to change people. It is my task to bear witness to them of One who loves them unconditionally, and who
can change them. For that I need God's help. No wonder the disciples needed Pentecost!
Grace and Peace,
Dennis B.