Sahih Muslim , Hadith 838 ⓘ
Abdullah b. Mughaffal reported Allah's Messenger u saying: There Is between the two calls (Adhan and Iqama) a prayer. And he mentioned it three times, and at the third time he said: This applies to those who wish to do it.
وَحَدَّثَنَا أَبُو بَكْرِ بْنُ أَبِي شَيْبَةَ، حَدَّثَنَا أَبُو أُسَامَةَ، وَوَكِيعٌ، عَنْ كَهْمَسٍ، قَالَ حَدَّثَنَا عَبْدُ اللَّهِ بْنُ بُرَيْدَةَ، عَنْ عَبْدِ اللَّهِ بْنِ مُغَفَّلٍ الْمُزَنِيِّ، قَالَ قَالَ رَسُولُ اللَّهِ صلى الله عليه وسلم " بَيْنَ كُلِّ أَذَانَيْنِ صَلاَةٌ - قَالَهَا ثَلاَثًا قَالَ فِي الثَّالِثَةِ - لِمَنْ شَاءَ " .
also referenced under: Book 6, Hadith 368 (In-Book) & Book 4, Hadith 1822 (USC-MSA)
This hadith has been narrated by Abdullah b. Mughaffal by another chain of transmitters, but with this variation that he (the Holy Prophet) said at the fourth time: " He who wishes (may do to)."
وَحَدَّثَنَا أَبُو بَكْرِ بْنُ أَبِي شَيْبَةَ، حَدَّثَنَا عَبْدُ الأَعْلَى، عَنِ الْجُرَيْرِيِّ، عَنْ عَبْدِ اللَّهِ، بْنِ بُرَيْدَةَ عَنْ عَبْدِ اللَّهِ بْنِ مُغَفَّلٍ، عَنِ النَّبِيِّ صلى الله عليه وسلم . مِثْلَهُ إِلاَّ أَنَّهُ قَالَ فِي الرَّابِعَةِ " لِمَنْ شَاءَ " .
also referenced under: Book 6, Hadith 369 (In-Book) & Book 4, Hadith 1823 (USC-MSA)