"Then Tashhad, then say the Iqamah." And they say that the meaning of Tashhad here is call the Adhan. An-Nasai recorded the Hadith with different chains (1054, 1137, 1314,1315). Whereas the wording narrated by At- Tirmidhi, and the author in Al-Kubra, mentions what the author mentioned in the chapter, the other cited versions that An-Nasai in this hook quoted do not. So it is as if he narrated the chain here for Hadith, indicating the same version that At-Tirmidhi narrated, and he himself in Al-Kubra, but he did not want to narrate the actual text here. Abu Dawud also narrated it with the order for the Adhan and Iqamah, through a different route of transmission (No. 861). And it is among the proofs used for the view that the Adhan and Iqamah are obligatory - since it has been ordered in the Hadith of the one who prayed incorrectly.  

أَنَّ رَسُولَ اللَّهِ ﷺ بَيْنَا هُوَ جَالِسٌ فِي صَفِّ الصَّلاَةِ الْحَدِيثَ