1Proverb: when in Rome, do as the Romans do — when you enter a new place or community, you should follow its local customs and rules. An older, more classical variant of 郷に入っては郷に従え; 入らば uses an archaic conditional form.
郷に入らば郷に従えというように、よその土地では謙虚に地元のやり方を学ぶものだ。
As the proverb 'when in Rome, do as the Romans do' teaches, in an unfamiliar place one should humbly learn the local ways.
祖父はよく「郷に入らば郷に従え」と言って、旅先では必ず地元の流儀を尊重していた。
My grandfather often said 'when in Rome, do as the Romans do,' and always respected local customs when traveling.