Introduction
A search of the W/H Greek NT and the LXX for μακαρι% οτι using a tool like the Unbound Bible, say, will reveal that the Beatitudes of Matthew 5 reveal a literary form that is particular to Jesus.
The form is:
Blessed ... because ...
The search is not exhaustive, of course, because verse boundaries prevent instances like Luke 10:23-24 being picked up, but it is sufficient to reveal Jesus' particular use of the form.
A search for instances of μακαρι%, alone, yields statements like Jesus uses in Luke 7:23 where the "because" is implicit.
So, it is reasonable to conclude that Jesus use of this form in Matthew 5, is deliberate, and sufficiently exclusive, such that the term "Beatitude" might be used to identify any expression that exhibits the same structure.
The Purpose of the Form
References: KJV
Note that the beatitudes are bracketed by reference to the "kingdom of heaven" in the first, Matthew 5:3, and the summation, in Matthew 5:12. Each need identified in a beatitude, will find its supply from the kingdom of heaven.
Blessed are the poor in spirit: for theirs is the kingdom of heaven.
Those in need of spiritual sustenance will seek out the kingdom of heaven and be fed (Matthew 6:33). Those who are not in need of such, are sustained by what they've found in the kingdom of earth.
Blessed are they that mourn: for they shall be comforted.
Those in need of comfort when death moves them to sorrow, will seek out the kingdom of heaven in order to find it, since reunion is its principle hope. Those who are not so moved have no such need, taking comfort in what they believe to be the finality of the grave. Jesus is unmistakeably identifying himself, here, with the same purpose as the prophet, in Isaiah 61.
This beatitude has particular relevance in regard to the death of Jesus (Matthew 24:30).
Blessed are the meek: for they shall inherit the earth.
The meek, who are not inclined to violence, are vulnerable and in need of protection and will seek out the kingdom of heaven to secure it. Those who are inclined to violence will seek out their own means of securing it from the resources available to them in the kingdom of the earth.
Jesus is making reference in this beatitude to Psalm 37, where the meek are those who rest in the LORD, in contrast to the wicked who prosper their way by bringing wicked schemes to pass. Jesus is also making a connection with Isaiah 11 and his role as the rod from the stem of Jesse.
I'll leave the exposition at this point, since exposition is not the function of this site. Three examples are sufficient to show the purpose of Jesus' particular use of this literary form. The reader can pursue their own study, if they have a mind, to verify how the given pattern continues throughout the passage, and that all the Beatitudes are moving towards the last, Matthew 5:11, which are then rounded off by the statement given in Matthew 5:12.