Most men hope to go to heaven when they die, but few, it may be feared, take the trouble to consider whether they would enjoy heaven if they got there. Heaven is essentially a holy place; its inhabitants are all holy; its occupations are all holy. To be really happy in heaven it is clear and plain that we must be somewhat trained and made ready for heaven while we are on earth…. No man can possibly be in a place where he is not in his element, and where all around him is not congenial to his tastes, habits and character. When an eagle is happy in an iron cage, when a sheep is happy in the water, when an owl is happy in a blaze of noonday sun, when a fish is happy in the dry land — then, and not till then will I admit that the unsanctified man could be happy in heaven.
J. C. Ryle, Holiness (Carlisle, PA: Evangelical Press, 2011), 22-23.