This is a popular verse at many funeral services. When a loved one passes from this life to the next the family members mourn the death of the deceased. If you keep this verse in context by reading verse 3 and 4 together you can see that the kind of mourning that Christ is talking about here is not mourning over the death of a loved one but mourning over sin. Jesus is saying blessed is that man who sins are forgiven, who has much sorrow and grief over his sinfulness, for he shall be comforted.
The questions that should ponder in the heart of a true believer are, why do I sin? Why do I do that which is displeasing unto God? 1 John 1:8-10 reminds us that even as saved children of God we fall short and sin. The words of John at the start of the next chapter is a great solace to the child of God he declares “And if any man sin, we have an advocate with the Father, Jesus Christ the righteous.” There is a time to mourn and a time to dance (Ecclesiastes 3:4) there must be a balance in the life of the Christian of mourning over our sins and joy over forgiveness.
In Revelation 21: 4 those that mourn shall be comforted by God when he wipes away all tears from their eyes. There is a day coming when sadness shall be turned to joy, when woe and heartache will cease in the soul of the believer. This promise of God is also found in Isaiah 61:2, “To proclaim the acceptable year of the LORD, and the day of vengeance of our God; to comfort all that mourn.”
The reader will do well to bear in mind James 4:7-10 this is how the believer is comforted by God. The truly mourning and repenting sinner will submit to the Lord as he is drawn nigh to the throne of grace. Humble thyself today before God and have your mourning turned to joy as your sin is confessed and God be glorified.