The speaker has just seen a windhover, another name for a kestrel, rising through a clear blue sky toward the sun. The first stanza is a quick snapshot of that moment, and the word "majestically" shows how impressed the speaker is. There is no story here, only the thrill of watching a bird in the air.
The second stanza turns inward. The speaker admits that words may not be enough to explain why the bird flies, or to capture how easily it spreads its wings. Instead, the flight is described as "a prayer," as if the bird's movement is a kind of worship. The last line suggests that watching it brings the speaker's soul real joy.
The mood is calm, uplifted and quietly reverent. The short lines and simple wording keep it light, almost like a held breath, which suits a brief moment of wonder. The title hints at the idea that flight needs no practical reason; its beauty is reason enough.