The Second Beatitude
Blessed are they who mourn,
for they shall be comforted.
But in this truth Jesus was talking about Christians mourning because they realize that they have sinned against a holy God and have brought dishonor to His name. This kind of dishonor of God's very name brings great mourning to the true believer. When a true believer sins they know that the sin just committed brings great pain and sorrow to God.
Only those who grieve over their sins under the conviction of the Holy Spirit and cry out to God, saying "Woe is me! I am a sinner. I am unclean. I have sinned against heaven and against you. I have sinned grievously. My sin is so great". They are the ones that will be comforted.
Why will only such people be comforted? Because they alone know that Jesus Christ came to seek and save that which is lost. They alone look to the cross of Jesus Christ and realize that Christ died for their sins.
Animations by Kitty