In just a few lines, the speaker describes a odd kind of lateness: not missing a train or an appointment, but missing a moment that has already gone by. The title, "Delayed," fits this well. The speaker can see the past, yet cannot step into it. It is like looking at something through glass, close enough to see but too late to join.
The second half shifts to the moon, whose light is what allows the speaker to see at all. There is a quiet irony in that, since moonlight is borrowed light, and the "silent bed" it seeks sounds like a place of rest or an ending. The speaker seems to feel regret, or maybe a gentle resignation. The mood is hushed, lonely and reflective, like a thought that comes late at night when everything else has gone still. Nothing dramatic happens, but a lot of longing is packed into very few words.