Blessed are the Mourners

Jesus says, "Blessed are those who mourn, for they shall be comforted."
What does He mean? Blessed because God is close to the broken-hearted? Blessed because God will bring comfort?
Nicholas Wolterstorff sheds an interesting light, "Mourners are aching visionaries...Mourners are those who have caught a glimpse of God's new day, who ache with all their being for that day's coming, and who break out into tears when confronted with its absence."
I cannot say it as well as him, so I will continue with his words.
"They are the ones who realize that in God's realm of peace there is no one blind and who ache whenever they see someone unseeing. They are the ones who realize that in God's realm there is no one hungry and who ache whenever they see someone starving. They are the ones who realize that in God's realm there is no one falsely accused and who ache whenever they see someone imprisoned unjustly. They are the ones who realize that in God's realm there is no one who fails to see God and who ache whenever they see someone unbelieving. They are the ones who realize that in God's realm there is no one who suffers oppression and who ache whenever they see someone beat down. They are the ones who realize that in God's realm there is no one without dignity and who ache whenever they see someone treated with indignity. There are the ones who realize that in God's realm of peace there is neither death nor tears and who ache whenever they see someone crying tears over death."
Even so come quickly Lord Jesus! Come bring your Kingdom. Come and bring comfort.