I found Keller’s explanation of “asymmetrical balance” to be helpful:
I believe that making disciples and doing justice relate (not exactly) but somewhat in the same way that faith and works relate to one another. We would say that faith alone is the basis for salvation, and yet true faith will always result in good works. We must not “load in” works as if they are an equal with faith as a salvation-base, but neither can we “detach” works and say that they are optional for a believer.
Similarly, I would say that the first thing I need to tell people when they come to church is “believe in Jesus,” not “do justice.” Why? Because first, believing in Jesus meets a more radical need and second, because if they don’t believe in Jesus they won’t have that gospel-motivation to do justice that I talk about in the book. So there’s a priority there.
On the other hand, for a church to not constantly disciple its people to “do justice” would be utterly wrong, because it is an important part of God’s will.
I’m calling for an ‘asymmetrical balance’ here. It seems to me that some churches try to “load in” doing justice as if it is equally important as believing in Jesus, but others, in fear of falling into the social gospel, do not preach or disciple their people to do justice at all. Both are wrong. A biblical church should be highly evangelistic yet known for its commitment to the poor of the city.
You can read the whole interview here.
You can also read the first chapter of the book online.