How can we be happy on earth knowing there are people in hell? The thought of hell has made me depressed.
Perhaps we can shed some light on this issue if we consider the knowledge that the blessed in heaven have of the damned. The blessed see God as he is in the Beatific Vision and consequently see with clarity his majesty and glory. This in turn allows them to see the horror of sin. The damned, therefore, are not pitied. The blessed see God’s justice in the damned being in hell. As such, they are happy even with such knowledge.
Here on earth, however, we do not enjoy such clarity of vision. For this reason the thought of people in hell causes sadness within us while on earth. We fail to appreciate the glory and majesty of God and the ugliness of mortal sin.
As long as we are on this side of the veil, there will be a sense of sadness within us when we think about the damned in hell. To the extent that we appreciate God’s majesty and justice and the horror of sin, our feelings of pity toward the damned will decrease.
For a detailed explanation of the blessed and their knowledge of the damned, see St. Thomas Aquinas’ Summa Theologiae Suppl. III:94:1-3.
You can also check out Karlo Broussard’s article “How Can One Be Happy in Heaven Knowing a Loved One is in Hell?” on the Catholic Answers website.