In this piece Dr. MacArthur says:

As a pastor in Southern California, I have the blessed privilege of mining the truth from God’s Word every week of my life. Doing that in Los Angeles only makes it more interesting, if for no other reason than the tremendous diversity of people, culture, and language here. When we take the gospel to our city, it’s amazing to watch God’s Word transcend the culture—and every false religion—to change lives. The message of salvation in Christ truly knows no hindrance.

If you think evangelism is a somewhat arduous task in that environment, you’re right. We face a culture that has rejected absolute truth and now considers it stylish to openly embrace and encourage degrading passions. The ecumenical, syncretistic spirit of the age recoils in horror at the exclusive claims of Christ. And popular, evangelical seeker-sensitive churches only make the task more difficult by refusing to confront sin in an effort to make the “unchurched” sinner comfortable.

You can read the rest at Grace To You.