Definition
This idiom is used to emphasize that rules or standards should be applied equally to everyone; if one person is allowed to do something, then another person should be allowed to do the same.
己所欲，亦勿施於人（適用於任何人）
She complained that if her brother could stay out late, then she should be able to as well, saying 'what's sauce for the goose is sauce for the gander.'
她抱怨說，如果她的兄弟可以晚歸，那麼她也應該可以，並說『適用於一方的標準也應適用於另一方』。
"If you allow him to do it, then I should be allowed to as well," he retorted, applying the principle of 'what's sauce for the goose is sauce for the gander.'
「如果你允許他這樣做，那麼我也應該被允許，」他反駁道，運用了『適用於一方的標準也應適用於另一方』的原則。
The manager told the employees that since the company requires them to be on time, the management should also follow the same rule, emphasizing that what's sauce for the goose is sauce for the gander.
經理告訴員工，既然公司要求他們準時，管理層也應該遵守同樣的規則，強調『適用於一方的標準也應適用於另一方』。