Keats describes his reaction to a Grecian urn painted with images of maidens, pipers and other Greeks. While the melody of modern day pipes may be sweet, Keats finds the painted pipes sweeter. They are not mere sensual pleasure, but guide one to a higher sense of ideal beauty. The other images have a similar effect, as they are frozen forever at the moment of highest perfection.
One part of the urn shows a youth about to kiss a maid. Keats envies the lover, for though he will never actually kiss his love, she will ever remain fair and they will forever be in love. The painted trees will also forever be perfect, never losing their leaves. When Keats' world passes away, this beautiful object will still remain and tell man that "Beauty is truth, truth beauty."
Keats urges his reader not to respond to melancholy by committing suicide. He says to avoid poisons like Wolf's-bane, nightshade, and yew berries. Instead, when most depressed, "glut thy sorrow" on the beauty of a rose or the rainbow of salt and sea. Likewise, if your mistress is angry with you, look into her eyes and feast on their ephemeral beauty.
Contrast is the key to pleasure. Melancholy is not the moment for death, but an opportunity for a fine experience. It is the fine balance between pain and pleasure that is ideal. The final stanza rephrases this idea. Beauty is always ephemeral; joy is always about to leave, but these are man's highest moments.
