后会暂无期相聚会有时
[hòu huì zàn wú qī xiāng jù huì yŏu shí]
'We do not know when we will meet again but believe someday will come'. It carries the feeling that the next time together is indefinite, maybe due to departure. There's a strong sense of sadness about separation here, but there's also the comfort of the expectation to meet eventually