expression
When in Rome, do as the Romans do
Proverb advising one to follow the customs of the place one is in. This is a slightly older or more literary form; the modern equivalent is 郷に入っては郷に従え.
See also: 郷に入っては郷に従え
海外に住むなら、郷に入らば郷に従えの精神が大切だ。
If you live abroad, the spirit of 'When in Rome, do as the Romans do' is important.
A Japanese rendering of the proverb 'When in Rome, do as the Romans do,' using classical conditional form 入らば (modern 入れば). The exact origin of the Japanese phrasing is uncertain, but it is a well-established calque.