In just a few short lines, the speaker turns time into a horse. Time has been preparing them for death, but it does so like a steady, dignified animal, "brave," "proud," and "of good purpose." The image softens something frightening. Instead of a hard countdown, we get a patient companion that walks beside the speaker, up and down, until evening arrives.
Evening here can be read as the later part of a life, though the poem never says so outright. The last two lines shift from acceptance to longing. The speaker misses "that hour or two" and pictures it as "lying in amber," a moment held perfectly still, the way an insect is preserved in resin. The mood is quiet and tender, with a little ache underneath. The speaker doesn't seem afraid of the grave, but they do miss a stretch of peaceful time that has passed and can't be walked through again.