Keller briefly addresses the skeptics who like to “dismiss Christians” by pointing to so-called “inconsistencies” in their application of Biblical teaching.
The article is not directed toward inconsistencies of Christians in their practice (i.e. obedience to the Lord). Rather, the thrust of the article is toward an explanation of the Bible’s consistency in its teaching, specifically explaining how to understand the context of various types of laws the Bible puts forward. The key to understanding is Jesus Christ.
For those who are sincere in the question of Biblical consistency in such things, this article provides a concise and solid answer.