A speaker watches someone old, probably a parent, struggle to drink from a cup. The hands are shaking, and the poem lingers on small details: one hand lifts, the other tries to calm the trembling liquid, and the saucer catches whatever spills. "Invisible lips" suggests the person is almost fading from view, even while sitting right there.
Then the poem looks back. These were hands that "knew things that others did not," strong enough to swing a child up "laughing with fear and love." The short, plain lines make that loss feel quiet and heavy.
The turn comes at the end. The speaker now has those hands, and they "gently lift and steady." The word "gloaming" means dusk, so the closing image is of a life darkening toward evening. The mood is tender and sad, but not bitter. The poem seems to say that care is handed down, and that love can mean returning what you were once given.