صحيح البخاري Sahih Bukhari كتاب الأذان The Book of Adhan
بَابُ بَدْءُ الأَذَانِ:

(1) Chapter. How the Adhan for Salat (prayer) was started.

2 hadith
Hadith 603
حَدَّثَنَا عِمْرَانُ بْنُ مَيْسَرَةَ ، حَدَّثَنَا عَبْدُ الْوَارِثِ ، حَدَّثَنَا خَالِدٌ الْحَذَّاءُ ، عَنْ أَبِي قِلَابَةَ ، عَنْ أَنَسٍ ، قَالَ : ذَكَرُوا النَّارَ وَالنَّاقُوسَ ، فَذَكَرُوا الْيَهُودَ ، وَالنَّصَارَى ، : ذَكَرُوا النَّارَ " فَأُمِرَ بِلَالٌ أَنْ يَشْفَعَ الْأَذَانَ وَأَنْ يُوتِرَ الْإِقَامَةَ " .
Narrated Anas: The people mentioned the fire and the bell (they suggested those as signals to indicate the starting of prayers), and by that they mentioned the Jews and the Christians. Then Bilal was ordered to pronounce Adhan for the prayer by saying its wordings twice, and for the Iqama (the call for the actual standing for the prayers in rows) by saying its wordings once. (Iqama is pronounced when the people are ready for the prayer).
Hadith Reference Sahih Bukhari / The Book of Adhan / Hadith: 603
Hadith Grading محدثین: أحاديث صحيح البخاريّ كلّها صحيحة
Hadith 604
حَدَّثَنَا مَحْمُودُ بْنُ غَيْلَانَ ، قَالَ : حَدَّثَنَا عَبْدُ الرَّزَّاقِ ، قَالَ : أَخْبَرَنَا ابْنُ جُرَيْجٍ ، قَالَ : أَخْبَرَنِي نَافِعٌ ، أَنَّ ابْنَ عُمَرَ كَانَ ، يَقُولُ : كَانَ الْمُسْلِمُونَ حِينَ قَدِمُوا الْمَدِينَةَ يَجْتَمِعُونَ فَيَتَحَيَّنُونَ الصَّلَاةَ لَيْسَ يُنَادَى لَهَا ، فَتَكَلَّمُوا يَوْمًا فِي ذَلِكَ ، فَقَالَ بَعْضُهُمْ : اتَّخِذُوا نَاقُوسًا مِثْلَ نَاقُوسِ النَّصَارَى ، وَقَالَ بَعْضُهُمْ : بَلْ بُوقًا مِثْلَ قَرْنِ الْيَهُودِ ، فَقَالَ عُمَرُ : أَوَلَا تَبْعَثُونَ رَجُلًا يُنَادِي بِالصَّلَاةِ ، فَقَالَ رَسُولُ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ : " يَا بِلَالُ قُمْ فَنَادِ بِالصَّلَاةِ " .
Narrated Ibn `Umar: When the Muslims arrived at Medina, they used to assemble for the prayer, and used to guess the time for it. During those days, the practice of Adhan for the prayers had not been introduced yet. Once they discussed this problem regarding the call for prayer. Some people suggested the use of a bell like the Christians, others proposed a trumpet like the horn used by the Jews, but `Umar was the first to suggest that a man should call (the people) for the prayer; so Allah's Apostle ordered Bilal to get up and pronounce the Adhan for prayers.
Hadith Reference Sahih Bukhari / The Book of Adhan / Hadith: 604
Hadith Grading محدثین: أحاديث صحيح البخاريّ كلّها صحيحة