Imam Nasa'i : 499

أَخْبَرَنَا أَبُو عَبْدِ الرَّحْمَنِ عَبْدُ اللَّهِ بْنُ مُحَمَّدٍ الْأَذْرَمِيُّ قَالَ حَدَّثَنَا عَبِيدَةُ بْنُ حُمَيْدٍ عَنْ أَبِي مَالِكٍ الْأَشْجَعِيِّ سَعْدِ بْنِ طَارِقٍ عَنْ كَثِيرِ بْنِ مُدْرِكٍ عَنْ الْأَسْوَدِ بْنِ يَزِيدَ عَنْ عَبْدِ اللَّهِ بْنِ مَسْعُودٍ قَالَكَانَ قَدْرُ صَلَاةِ رَسُولِ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ الظُّهْرَ فِي الصَّيْفِ ثَلَاثَةَ أَقْدَامٍ إِلَى خَمْسَةِ أَقْدَامٍ وَفِي الشِّتَاءِ خَمْسَةَ أَقْدَامٍ إِلَى سَبْعَةِ أَقْدَامٍ

Narrated to us [Abu Abdurrahman Abdullah bin Muhammad Al Adzrami] he said : [Abidah bin Humaid] Narrated to us from [Abu Malik Al Ashja'i Sa'ad bin Thariq] from [Katsir bin Mudrik] from [Al Aswad bin Yazid] from [Abdullah bin Mas'ud] he said : "The size of the prayer of the Messenger of Allah (peace and blessings of Allah be upon him) at the time of Dhuhr during the summer is three to five (shadows) of the soles of the feet, and in the winter five to seven (shadows) of the soles of the feet."