Heaven would be a very hell

(Thomas Brooks, "The Crown and Glory of Christianity,
 or, HOLINESS, the Only Way to Happiness", 1662)

"Yet they say to God—Leave us alone! We have no
 desire to know Your ways." Job 21:14

Heaven would be a very hell to an unholy heart.
If now—the presence of God in His servants, and the
presence of God in His ordinances—is such a hell to
unholy souls; ah, what a hell would the presence of
God in heaven be—to unholy hearts!

It is true, an unholy heart may desire heaven—as
it is a place of freedom from troubles, afflictions,
oppressions, vexations, etc., and as it is a place of
peace, rest, ease, safety, etc. But this is the least
and lowest part of heaven.

To desire heaven as it is . . .
  a place of purity,
  a place of grace,
  a place of holiness,
  a place of enjoying God, etc.
—is above the reach of an unholy heart.

The company of heaven are all holy,
the employments of heaven are all holy,
the enjoyments of heaven are all holy—
therefore heaven would be a most undesirable
thing to unholy hearts.

An unholy heart is no way desirous nor ambitious
of such a heaven . . .
  as will rid him of his darling sins,
  as will make him conformable to a holy God,
  as will everlastingly divorce him from his precious lusts,
  as will link him forever to those gracious souls whom
he has scorned, despised, and persecuted in this world.