Respect gender boundaries when performing wudhu.

This hadith is about the importance of gender separation when it comes to performing ablution, or wudu. Wudu is a ritual washing that Muslims do before prayer, and this hadith teaches us that men should not use the same water as women for their wudu. This is because Islam places a great emphasis on modesty and respect between genders, so it is important to maintain physical boundaries between them in order to preserve these values. It also teaches us that we should be mindful of our actions and how they may affect others, even if it seems like a small thing such as using someone else's leftover water.