What is the Letter of Farewell to the Dutchman Du's Appointment used to send letters to friends far away?

Say goodbye to the viceroy and go to Bo for his post.

Across the wall of Sanqin, across a layer of fog, across a river.

We said goodbye sadly, and our two officials went in opposite directions.

However, as long as China keeps our friendship, heaven will remain our neighbor.

Why linger at the fork in the road, the child is stained with towels.

When friends leave, they give poems as a sign of farewell. Among them, the famous sentence "However, China holds our friendship and keeps our neighbors in heaven" is to comfort friends, brothers in the world, and the pattern is great, which is praised by future generations.