(proverb) people will meet again at some point eventually, it implies not to treat others badly in order to avoid future revenge; 'paths will cross again someday'
Definitions (粵典–words.hk)
語句
指日後總有再次相遇、打交道嘅機會，勸人行事唔好做得太絕，要留有餘地；有時會用作恐嚇，意思係遲早有一日會返嚟尋仇。 a saying which implies that two people will meet again, or to say how small the world is ; sometimes would be used as a threat, meaning that the speaker will catch up one day with the addressee. Literally: mountains and rivers meet
世姪，山水有相逢，無謂做到咁盡啦。
世姪，山水有相逢，无谓做到咁尽啦。
Son, two people will meet again in this small world, you don't have to make everything to an extreme.
我唔會就咁算數架，記住山水有相逢，你哋睇住嚟。
我唔会就咁算数架，记住山水有相逢，你哋睇住嚟。
I won't forget what happened today, remember how small the world is, you better watch your back.
近義詞
凡事留一線，他日好相見
Examples (粵典–words.hk)
Cantonese
世姪，山水有相逢，无谓做到咁尽啦。
世姪，山水有相逢，無謂做到咁盡啦。
Son, two people will meet again in this small world, you don't have to make everything to an extreme.
Cantonese
我唔会就咁算数架，记住山水有相逢，你哋睇住嚟。
我唔會就咁算數架，記住山水有相逢，你哋睇住嚟。
I won't forget what happened today, remember how small the world is, you better watch your back.