friends must part 天下无不散之宴席；聚散离合总有时；送君千里，终须一别

【例句】
Even as the best of friends must part, we shall hold on to our friendship.
即便是天下无不散之宴席，我们都会珍惜彼此间那份情谊。

Friends must part，we should cherish the beautiful time now.
天下无不散之筵席，我们要珍惜现在的美好时光。