"[Falah uqsimu] The meaning is: 'I do swear,' and 'la' (in the original text) is redundant. [Bil-khunnas] The interpretation of al-Hasan is: they are the stars that retreat during the day, meaning: they hide, while continuing their course during that time."
﴿فَلَا أقسم﴾ الْمَعْنى: فأقسم ((وَلَا)) صلَة ﴿بالخنس﴾ تَفْسِيرُ الْحَسَنِ: هِيَ النُّجُومُ تخنِسُ؛ بِالنَّهَارِ أَيْ: تَتَوَارَى، وَهِيَ فِي ذَلِك جَارِيَة