We begin today a series on the relationship of the kingdom of God to the Church and I do so for several reasons:
First, I have long wanted to sort out the evidence in the Gospels and Epistles again. I did some very serious work on kingdom in the 80s and 90s but have felt a need to return to that same evidence with new questions.
Best book on kingdom: See GR Beasley-Murray, Jesus and the Kingdom of God.

Second, many today have chosen to prefer “kingdom” over “church” in a way that is not unlike this idea: as I like Jesus instead of the Church, so I like kingdom instead of Church. This concerns me, and it concerns me deeply. It plays off the distinction between kingdom and church in a way that is out of line with what the New Testament says.
Third, in the history of the Church, many have either equated or come close to equating kingdom with the Church. E.g., Augustine, many Roman Catholics (and I assume Eastern Orthodox), and in some ways in the Reformed traditions. Today’s rather cavalier playing off of these two concepts, then, needs to be more respectful of these Church traditions, even if it disagrees with them. (It bothers me when folks dismiss this view without really even knowing about the history.)
Fourth, Dispensationalism has at times (what it is now is no longer what it was) made a radical distinction between kingdom and Church, not unlike our “second” point, but with a different set of factors: kingdom being more related to Israel and God’s governance in earthly terms and Church being a spiritual organism. The second group tends to eliminate Israel from “kingdom of God”, sees kingdom as justice and peace and good government in this world, and see the Church in other terms (though I’m not always sure where this group might be on this question).
Fifth, George Ladd’s famous discussion in his NT Theology (chp 8.), the book on which my generation cut its teeth, defines “kingdom” as a dynamic relationship with God and therefore the kingdom “is never to be identified with the church” (109). This is a non sequitur in my judgment, but it is also our QED — what we are looking at in this series.
Ladd’s points:
1. NT does not equate believers with kingdom. But he presses on both Matt 13:41 and 16:18-19. But, we’ll look at this too.
2. The kingdom creates the church. This assumes the point and explains church as following the kingdom.
3. The church witnesses to the kingdom. True, but beside the point. One can reverse it: kingdom people witness to the church.
4. The church is the instrument of the kingdom. Same weakness; it is explaining the point rather than proving the point.
5. The church is the custodian of the kingdom. Same.
Here we go then… creates, witnesses, is the instrument, and custodian are not arguments but explanations … each assumes that the two are not the same and explains the one vis-a-vis the other. I want to challenge this but I want to challenge it by looking at the texts in the Gospels to see if these explanations are the best explanations.
Sixth, to a different subject: the singular background to “kingdom” for Jesus must be kept at a general level for now: kingdom arrival, as Jesus teaches it, must mean the fulfillment of Old Testament and Jewish expectations for the society God has always intended for Israel/God’s people. [The idea that “kingdom” means simply “heaven” in life beyond death is a reduction; there is continuity between kingdom and heaven, but the two are not synonyms though many seem to use the terms this way.]
There are tons of things to say … they’ll all come up in the series and in the comments you will offer. Tomorrow I begin with Mark 1:15.