Al-Kāfi - Volume 3 > Construction of the Masjid of the Holy Prophet
Hadith #3

3ـ أَحْمَدُ بْنُ إِدْرِيسَ وَغَيْرُهُ عَنْ أَحْمَدَ بْنِ مُحَمَّدٍ عَنْ عَلِيِّ بْنِ إِسْمَاعِيلَ عَنْ مُحَمَّدِ بْنِ عَمْرِو بْنِ سَعِيدٍ قَالَ حَدَّثَنِي مُوسَى بْنُ أُكَيْلٍ عَنْ عَبْدِ الأعْلَى مَوْلَى آلِ سَامٍ قَالَ قُلْتُ لأَبِي عَبْدِ الله (عَلَيْهِ الْسَّلام) كَمْ كَانَ مَسْجِدُ رَسُولِ الله (صلّى اللهُ عَلَيْهِ وَآلِه) قَالَ كَانَ ثَلاَثَةِ آلاَفٍ وَسِتَّمِائَةِ ذِرَاعٍ تَكْسِيراً.

3. Ahmad ibn Idris and other people have narrated from Ahmad ibn Muhammad from Ali ibn ’Isma‘il from Muhammad ibn ‘Amr ibn Sa‘id who has said that Musa ibn ‘Ukayl narrated from ‘Abd al-‘A’la’ from Mawla Ala Sam who has said the following: “I asked abu ‘Abd Allah, ‘Alayhi al-Salam, ‘What was the size of Masjid of the Messenger of Allah?’ He (the Imam) replied, ‘It was three thousand and six hundred square yards.’”