أَخْبَرَنَا عَلِيُّ بْنُ حُجْرٍ، قَالَ أَنْبَأَنَا إِسْمَاعِيلُ، عَنْ خَالِدٍ الْحَذَّاءِ، عَنْ أَبِي قِلاَبَةَ، عَنْ مَالِكِ بْنِ الْحُوَيْرِثِ، قَالَ قَالَ لِي رَسُولُ اللَّهِ صلى الله عليه وسلم وَلِصَاحِبٍ لِي ‏"‏ إِذَا حَضَرَتِ الصَّلاَةُ فَأَذِّنَا ثُمَّ أَقِيمَا ثُمَّ لْيَؤُمَّكُمَا أَحَدُكُمَا ‏"‏ ‏.‏

It was narrated that Malik bin Al-Huwayrith said: "The Messenger of Allah (PBUH) said to me and to a companion of mine: 'When the time for prayer comes, let the two of you call the Adhan then the two of you say Iqamah, then let one of you lead the prayer.'" Translation Not Available

Book Ref: Sunan An Nisai Book 7 Hadith 677
Web Ref:  Sunan An Nisai Vol 1 Book 7 Hadith 670