What is the falling out between Tullian Tchividjian and The Gospel Coalition about?

The proximate cause appears to be a falling out over allegations of a sexual abuse coverup, which Tchividjian blogged about publically.

According to Christianity Today, Maheny was accused of covering up sexual abuse, and Tchividjian couldn't associate himself with that.:

Mahaney resigned from The Gospel Coalition (TGC) last weekend in the wake of the criminal conviction of a former youth leader who abused three boys at SGM's flagship, Covenant Life Church (CLC), while Mahaney was lead pastor. On Wednesday, TGC founders Tim Keller and Don Carson gave their explanation of Mahaney's resignation, as well as that of Joshua Harris, CLC's pastor after Mahaney, from TGC's then 50-person council. (They also explained TGC's recent request for Tullian Tchividjian to remove his blog from the Reformed network. Subsequent to the removal request, Tchividjian has publicly criticized how TGC members have responded to the allegations against Mahaney and SGM.)

This position is reflective of the allegations by Coral Ridge Presybterian's pastor, Tullian Tchividijan who is quoted in The Christian Post as writing:

"Give me a break. These people, they're family. Of course he knew," Tchividjian told The Christian Post. "C. J. was, for many years, the micro-managing head of the organization and nothing happened under the umbrella of Sovereign Grace that he wasn't made aware of, so for anyone to say, 'Well he didn't know,' that's totally naive."

Furthermore, the same article states as background:

C. J. Mahaney, who founded the SGM, along with other ministry leaders, was hit with a civil lawsuit last year alleging that they conspired to "permit sexual deviants to have unfettered access to children for purposes of predation and to obstruct justice by covering up ongoing past predation."

While the lawsuit was thrown out due to statute of limitations, Tchividjian said that unlike many of those connected to TGC who considered Mahaney a friend and claimed that he had "been the object of libel and even a Javert-like obsession by some," he saw the situation differently. In his eyes, given that Mahaney's brother-in-law and fellow former pastor at Covenant Life Church had confessed to knowing about sex abuse claims and withholding that information from police last week, the SGM pastor was guilty.

There is a longer interview here.

For his part, Mahaney denies the claims, saying:

"I look forward to the day when I can speak freely," said Mahaney. "For now, the simple and extraordinarily unsatisfying reality—for myself and others—is that in the face of an ongoing civil lawsuit, I simply cannot speak publicly to the specifics of these events. "Even with those constraints, however, let me be clear about this: I have never conspired to protect a child predator," Mahaney continued, "and I also deny all the claims made against me in the civil suit."

There does appear to be reconciliation, however - From this article in Christianity Today:

Tchividjian also affirmed his friendship with TGC co-founder Tim Keller, and emphasized that TGC and his Liberate ministry are "on the same team" because "the harvest is ripe enough for well-meaning brothers and sisters to agree to disagree."

Meanwhile, Russell Moore wrote that he is more in agreement with TGC than Tchividjian on the sanctification debate, but the Ethics and Religious Liberty Commission president praised the apology as "something we all can learn from, and ought to reflect on."

He also compared it to how conservative Christians received World Vision's apology for attempting to hire gay Christians in legal same-sex marriages. "Our attitude should have been, from the beginning, to show faith working itself out in love," wrote Moore. "That means believing the best about another, unless proven otherwise."

Postscript:

This entry mentions that there are differences in regards law and grace - and that there are accusations of Maheny using grace to cover for sin. That may be the doctrinal differences being talked about, but let's face it: even if the doctrinal differences are about the degree to which a pastor should exercise grace or justice when dealing with accusations of child abuse, the truth is, even as the announcement says, "the matters are pastoral"

Tullian, in his blog, mentions that over the past several years he felt the messaging of the Gospel Coalition had changed (he used the word "morphed") to the point where he was finding himself for drawn to Liberate's specific message, also saying that

"So, now is the right time to pull the trigger. In fact, it's probably over due.

It was also noted that he publicly criticized (and I say publicly because it was an interview, which was made public) members of TGC for their defense of CJ Mahaney:

"the good-old boys club covering up with own"

as well as

"I've just been sort of disgusted by the whole thing." As well as alleging that CJ Mahaney knew about what was going on.

We then have Tim Keller and Don Caron who said he was "asked to leave" because of the sanctification debate, which they said it was becoming apparent that "the dispute was becoming increasingly sharp and divisive."

Tullian said his decision to leave was his own, but the timing was TGC's doing. According to him, no one had even said anything before he was told to leave:

"No one ever said anything to me from the Gospel Coalition staff, not Don Carson, Tim Keller, the president, the vice president, no one from the Gospel Coalition ever even uttered a word about concern, which is why, when I was told 'You need to go immediately,' I was shocked."

Tullian does not believe it a result of clashing theology, and he himself summed it up best here I think:

"Theology is not to blame here. You can't blame theology for the way that you handle it. It's good theology in the hand of bad sinners. That becomes dangerous," said Tchividjian. "When the Christian faith becomes little more than theological propositions and categories, you're not actually thinking about how theology serves people, it can become divisive."

http://www.gospelherald.com/articles/51352/20140524/tullian-tchividjian-refutes-tim-keller-d-a-carsons-gospel-coalition-statement-on-his-exit.htm

EDIT: Here's a little bit more from his article with the Christian Post. It appears TGC started taking on a very critical, we're right-your wrong vibe that he didn't agree with. The following is an excerpt:

Tchividjian believes that some at TGC have adopted a very critical tone. “I think that’s their tone. That has become their tone. That’s not the tone of everybody there but that is the tone of some prominent voices there: critical, very, very quick to point out what’s theologically wrong out there, very slow to pick apart what’s theologically wrong in here in terms of their own position … and I think people pick up on that,” he said. Tchividjian, who considers himself Reformed, noted that just because these voices also considered themselves Reformed, one should not see their behavior as the fruits of their doctrine.

“Theology is not to blame here. You can’t blame theology for the way that you handle it. It’s good theology in the hand of bad sinners. That becomes dangerous,” said Tchividjian. “When the Christian faith becomes little more than theological propositions and categories, you’re not actually thinking about how theology serves people, it can become divisive.“ “Anytime you associate yourself with a movement, you think that is at the center of the universe, and there is a much larger Christian and Evangelical world out there that is now looking at The Gospel Coalition, which seemed to start out as a positive movement that was for Gospel centrality and cultural engagement,” continued Tchividjian. “And now the tone from all the people I hear and my opinion is very much ‘what we’re against.‘ People just aren’t attracted to that.”