Tim Keller is well-known for his “urban mandate” theology where he twists Genesis 1:28 into a dominionist mandate for Christians to move into the cities in droves and assimilate to the culture and contextualize the gospel in order to turn urban areas into Christian cities.
In Keller’s theology, he places a high view on such things as art and entertainment–of which there is precious little mention of at all in the Scriptures–and insists that churches need to gather the input of the community on their worship music style and other Evangelistic activities in order to reach them.
Keller’s theology has a lot in common with the New Apostolic Reformation’s “Seven Mountain Mandate” which teaches that Christians are called to take over seven “areas” of culture and Christianize them in order to “redeem” the culture. Keller’s twist on this is that Christians need to “redeem” the urban cities by a similar methodology. Keller’s view is largely rooted in his social justice gospel–a false gospel that has been thoroughly refuted.
John MacArthur, on the other hand, actually correctly exegetes the Scriptures and explains exactly what the biblical “urban mandate” is, and it’s to go into these cities and warn them of the wrath of God to come and call them to repentance.