"I asked Ibn 'Umar about the Adhan and he said: 'At the time of the Messenger of Allah ﷺ, the phrases of the Adhan were recited twice and the phrases of Iqamah once, except that you should say (the phrase) Qad qamat is-salah (prayer is about to begin)twice. When we heard 'prayer is about to begin' we would perform Wudu' and go out to pray.'"  

كَانَ الأَذَانُ عَلَى عَهْدِ رَسُولِ اللَّهِ ﷺ مَثْنَى مَثْنَى وَالإِقَامَةُ مَرَّةً مَرَّةً إِلاَّ أَنَّكَ إِذَا قُلْتَ قَدْ قَامَتِ الصَّلاَةُ قَالَهَا مَرَّتَيْنِ فَإِذَا سَمِعْنَا قَدْ قَامَتِ الصَّلاَةُ تَوَضَّأْنَا ثُمَّ خَرَجْنَا إِلَى الصَّلاَةِ