| Quote #1
Thou foster-child of Silence and slow Time, (line 2)
Time moves slowly on the urn. Its lifespan is much longer than ours, and so changes happen to it much more gradually. But "slow" is only a relative term. In the history of the universe, for example, the time between Ancient Greece and modern times is a mere blink of the eye.
| Quote #2
Fair youth, beneath the trees, thou canst not leave
The speaker keeps playing the same card again and again: pretending that the people on the urn live in the same moment forever. There is no transience in this world. For the lover, it’s a trade-off. He never gets to make out with his lady, but he always wants to make out with her. You may have heard the famous Shakespeare quote, "Better to have loved and lost than never to have loved at all." This poet adds a twist. He’s like, "The best thing would to be always to love but never to ‘have loved.’" This, obviously, is a contradiction and a fantasy, but that doesn’t lessen the power of the idea.
| Quote #3
For ever warm and still to be enjoy'd,
Line 26 sounds more like a steaming steak dinner than a person, but you get the idea: the lovers are always on the verge of satisfaction but never achieve it because things don’t change in the world of the urn. Where there is transience, there is the possibility of getting sick of the things you love: instead of a tender desire, love becomes a frustrating "thirst" that keeps coming back.