WHY CONVERSION AND REVIVAL ARE BIBLICAL
Reading this I am assured of Dr. Keller's proper reformed stand. He's not one of those who would 'consider' social gospel as the PC(USA) would. "...[they], have, I believe, taken a wrong turning in pitting corporate Body Life against revival and conversion".
It can be argued that Keller's disinterest of confrontational debate in public is due to his goal in evangelism. Which often times brought question as to if it was just a matter of cowardice.
In order to encourage readers, perhaps the nominal christians in particular, to seek revival, Keller defeats the social gospelians with key verses on circumcision of the heart (Jeremiah 4:4; cf. Deuteronomy 10:16, 30:6; Joel 2:13, and Acts 8:13, 21-23).
It would appear that he also desired to bend verses in Ephesians 2:22 and Colosians 2:9-10 to his point. "This must mean that while these things are objectively true of Christians, the Spirit can make these truths so spiritually real...". Contrasting Calvin's commentary on Eph 2:22 "...to remind them that all human exertions are of no avail without the operation of the Spirit...", one finds that Keller's emphasis on "all Christians already have Christ..." smudges on the definition of the elects.
Having an non-offensive approach may be persuasive to the crowd towards conversion, yet the lack of discipline could easily dilute the gospel and obscure the fear of God.
So instead of describing 2 Peter 1:9 as referring to those who are "near-sighted" Christians, I believe it is better to stick to the point of that verse, that it's addressing those who need this warning, to wake up, realizing what they ought as Christians. So true Christians, will make their election sure, diligently, and not be as the blind and forgetful.