كتاب صلاة المسافرين وقصرها
6  
The Book of Prayer - Travellers
(9)
Chapter: It is disliked to start a voluntary prayer after the Mu’adhdhin has started to say Iqamah for prayer, whether that is a regular sunnah, such as the sunnah of Subh or Zuhr, or anything else, and regardless of whether he knows that he will catch up with the rak`ah with the Imam or not
(9)
باب كَرَاهَةِ الشُّرُوعِ فِي نَافِلَةٍ بَعْدَ شُرُوعِ الْمُؤَذِّنِ ‏
Sahih Muslim 712

'Abdullah b. Sarjis reported:

A person entered the mosque, while the Messenger of Allah (ﷺ) was leading the dawn prayer. He observed two rak'ahs in a corner of the mosque, and then joined the Messenger of Allah (ﷺ) in prayer. When the Messenger of Allah (ﷺ) had pronounced salutations (he had concluded the prayer), he said: O, so and so, which one out of these two prayers did you count (as your Fard prayer), the one that you observed alone or the prayer that you observed with us?
حَدَّثَنَا أَبُو كَامِلٍ الْجَحْدَرِيُّ، حَدَّثَنَا حَمَّادٌ يَعْنِي ابْنَ زَيْدٍ، ح وَحَدَّثَنِي حَامِدُ بْنُ عُمَرَ الْبَكْرَاوِيُّ، حَدَّثَنَا عَبْدُ الْوَاحِدِ يَعْنِي ابْنَ زِيَادٍ، ح وَحَدَّثَنَا ابْنُ نُمَيْرٍ، حَدَّثَنَا أَبُو مُعَاوِيَةَ، كُلُّهُمْ عَنْ عَاصِمٍ، ح وَحَدَّثَنِي زُهَيْرُ بْنُ حَرْبٍ، - وَاللَّفْظُ لَهُ - حَدَّثَنَا مَرْوَانُ بْنُ مُعَاوِيَةَ الْفَزَارِيُّ، عَنْ عَاصِمٍ الأَحْوَلِ، عَنْ عَبْدِ اللَّهِ بْنِ سَرْجِسَ، قَالَ دَخَلَ رَجُلٌ الْمَسْجِدَ وَرَسُولُ اللَّهِ صلى الله عليه وسلم فِي صَلاَةِ الْغَدَاةِ فَصَلَّى رَكْعَتَيْنِ فِي جَانِبِ الْمَسْجِدِ ثُمَّ دَخَلَ مَعَ رَسُولِ اللَّهِ صلى الله عليه وسلم فَلَمَّا سَلَّمَ رَسُولُ اللَّهِ صلى الله عليه وسلم قَالَ ‏ "‏ يَا فُلاَنُ بِأَىِّ الصَّلاَتَيْنِ اعْتَدَدْتَ أَبِصَلاَتِكَ وَحْدَكَ أَمْ بِصَلاَتِكَ مَعَنَا ‏"‏ ‏.‏
Reference : Sahih Muslim 712
In-book reference : Book 6, Hadith 81
USC-MSA web (English) reference : Book 4, Hadith 1537
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