تصبح على خير

You use this phrase when you are leaving. Use it when you are going to sleep. You must change the verb for the person. For a man, say Tusbih 'ala khayr. For a woman, say Tusbiheen 'ala khayr. For a group, say Tusbihu 'ala khayr. The most common response is Wa anta min ahlihi. This means 'And you are from the people of goodness.' It is a polite verbal dance. It feels very cozy and respectful.

Use it when finishing a late-night phone call. Say it when leaving a friend's house after dinner. It is perfect for texting someone before you sleep. Use it with your family before heading to your room. Even in a professional late-night meeting, it works well. It signals that the interaction is over for the day. It is the verbal equivalent of turning off the lights. You will hear it in every Arabic-speaking country.

Do not use this when you first arrive. If it is 9 PM and you just met, say Masa' al-khayr. That means 'Good evening.' Only use Tusbih 'ala khayr when someone is actually going to sleep. Do not say it at 4 PM, even if you are tired. It sounds strange if the sun is still up. Also, do not use it if you plan to see them again in ten minutes. It is a final goodbye for the night.

Arabic culture places a high value on hospitality and well-wishing. Every greeting often has a specific, beautiful response. This phrase reflects a history of wishing for safety during the night. In the past, the night could be a dangerous time. Wishing someone 'goodness' in the morning was a serious prayer. Today, it remains a staple of daily kindness. It connects the end of one day to the hope of the next. It is a very optimistic way to sleep.

In Lebanon or Syria, you might hear Laila Sa'ida. This means 'Happy night.' It is a bit more formal. In Egypt, people might just say Tisbah 'ala khayr with a local accent. Some people add Ahlam Sa'ida which means 'Sweet dreams.' If you want to be very religious, you might say Fi aman Allah. This means 'In God's protection.' However, Tusbih 'ala khayr remains the undisputed king of bedtime phrases. It works everywhere from Morocco to Iraq.