Observe Witr prayer before it is morning. Abu Sa'id reported that they (the Prophet's Companions) asked the Messenger of Allah ﷺ about Witr (prayer). (In reply to their inquiry) he said: Observe Witr prayer before it is morning. (Using translation from Muslim 754a)
أَنَّ النَّبِيَّ ﷺ قَالَ «أَوْتِرُوا قَبْلَ أَنْ تُصْبِحُوا»