Matthew 5:4 (BSB)

Blessed are those who mourn, for they will be comforted.

From Matthew 5. Also in the ESV.

Commentary on Matthew 5:4

• John Calvin (Reformed), Calvin's Commentaries on Matthew 5:4: 4. Happy are they that mourn. This statement is closely connected with the preceding one, and is a sort of appendage or confirmation of it. The ordinary belief is, that calamities render a man unhappy. This arises from the consideration, that they constantly bring along with them mourning and grief. Now, nothing is supposed to be more inconsistent with happiness than mourning.
• Matthew Henry (Presbyterian), Matthew Henry's Complete Commentary on Matthew 5:3-12: Christ begins his sermon with blessings, for he came into the world to bless us (Act 3:26), as the great High Priest of our profession; as the blessed Melchizedec; as He in whom all the families of the earth should be blessed, Gen 12:3.
• John Gill (Reformed Baptist), Exposition of the Old and New Testaments on Matthew 5:4: Blessed are they that mourn,.... For sin, for their own sins; the sin of their nature, indwelling sin, which is always working in them, and is a continual grief of mind to them; the unbelief of their hearts, notwithstanding the many instances, declarations, promises, and discoveries of grace made unto them; their daily infirmities, and many sins of life, because they are committed against a...
• Albert Barnes (Presbyterian), Barnes' New Testament Notes on Matthew 5:4: Verse 4. Blessed are they that mourn. This is capable of two meanings: either that those are blessed who are afflicted with the loss of friends or possessions; or that they who mourn over sin are blessed. As Christ came to preach repentance, to induce men to mourn over their sins, and to forsake them, it is probable that he had the latter particularly in view, .