God blesses those who mourn,
for they will be comforted.
Matthew 5:4
Matthew 5:4 is part of the Beatitudes, a series of statements made by Jesus in the Sermon on the Mount. Blessed means more than an emotional state, it's a spiritual condition that comes from being in a right relationship with God.
The word "mourn" here doesn't just refer to grieving over the loss of a loved one, it also refers to a deep sorrow over sin, both personal and corporate. It is an active sharing of the world’s hurt and sin with Jesus. Therefore, it includes not only sorrow for one’s own sin, but also sorrow because of the world’s appalling condition, its rejection of the Savior, and the doom of those who refuse His mercy.
The promise in this verse is that those who mourn in this way will be comforted. This comfort comes from God Himself. It's the comfort of forgiveness, of restoration, of knowing that God is with us in our pain and sorrow. It's the comfort of the Holy Spirit, who is called the Comforter (John 14:16). These mourners shall be comforted in the coming day when “God shall wipe away every tear from their eyes” (Rev. 21:4).
Believers do all their mourning in this life; for unbelievers, today’s grief is only a foretaste of eternal sorrow.
—Faith