A man said, "O Messenger of Allah ﷺ! How is the prayer of the night?" He said, "Two rakʿat followed by two rakʿat and so on, and when you apprehend the approaching dawn, offer one rakʿa as witr." (Using translation from Bukhārī 1137)
قَالَ النَّبِيُّ ﷺ صَلَاةُ اللَّيْلِ مَثْنَى مَثْنَى فَإِذَا خِفْتَ الصُّبْحَ فَأَوْتِرْ بِوَاحِدَةٍ