According to Rob Bell, that's not the God he knows. Nor is it the God I believe is described in the Bible. Jesus Christ, The Lord God of all Creation, is a God of forgiveness (Eph 1.7). Anyone who genuinely seeks forgiveness from God, and who repents of their sin (i.e. to simply admit our wrong, accept His forgiveness, and ask for His help to stop doing what is wrong and to start living in a way that pleases Him) "will not perish, but have eternal life." (Jn 3:16) That's not my opinion. That's God's promise to us.
And Jesus paints a very different picture of those who spend eternity in Hell. He describes unrepentant sinners. He says that they will be "weeping and gnashing their teeth." He says that seven times, in fact.
Some people mistakenly think of "weeping and gnashing of teeth" as describing remorse, as regret about bad choices made and missed possibilities: "Oh, if I only knew, if I only did this or that, Oh, whoa is me."
We think of these poor souls -- maybe our family or our friends -- as living in this regret that simply boils down to, as Robert Frost might say, "the road not taken." They made mistakes, unfortunate bad choices in their short time on earth, and now must pay an outrageous price ... for eternity? That seems unfair, say those who agree with Rob Bell. Kind of like getting a life sentence for jay walking.
But the same words Jesus uses for "gnashing of teeth" are also used in scripture accounts that have nothing to do with hell, and in these examples, you can't associate "gnashing of teeth" with anything resembling remorse or regret. For example, in Acts 7:54, the religious mob who stoned Stephen to death are described as being "furious and gnashed their teeth at him."
Here are other examples from scripture:
