The same promise, twice, at the edges
Of the eight beatitudes, only the first and the last share identical wording: "for theirs is the Kingdom of Heaven." Every reward in between is different. That repetition is not incidental — it is a frame.
A list that begins and ends with the same words is doing something a list with eight different endings is not. The middle six beatitudes each receive their own distinct promise — comfort, inheritance, satisfaction, mercy, sight, sonship — all of them future in feel. But the first beatitude closes with "for theirs is the Kingdom of Heaven," and so does the last.
Remove that closing repetition and you lose more than a parallel. You lose the enclosure. With it in place, the list has two edges made of the same material, and everything else sits between them.
What the frame asks, quietly, is whether the two occupants of those edges belong together. The first is the 'poor in spirit' — a condition entirely interior, a kind of inward vacancy. The last is those who have been persecuted for righteousness — a condition entirely exterior, a cost paid in public. One pole faces inward, the other outward. Yet both receive not a future reward but a present-tense possession: not 'they will receive' but "theirs is."
The frame gives the identical gift to the one who begins with nothing inside and the one who has lost something outside.