What does it mean to bid farewell to ancient poetry in the mountains?

Friend, I once watched you go down the mountain: poem: After seeing you off in the mountain.

Farewell in the mountains

(Tang) Wang Wei

My friend, I watched you go down the mountain,

Until now, in the dark, I closed the thatched door.

The grass turns green again in spring,

But my friend prince, will you? ?

Note (1) cover: closed; (2) Chai Fei: Chai Men; (3) Wang Sun: the son of a noble, here refers to the friend who sent him away.

After seeing you off on the mountain,

As the sun sets, I close Chai Men.

When the spring grass turns green again next year,

Friend, can you come back?

Thoughts and feelings: thoughts and feelings of missing friends and expecting their early return.