When the adhān has finished
Whoever says this after hearing the call will have the Prophet's ﷺ intercession on the Day of Rising.
مَنْ قَالَ حِينَ يَسْمَعُ النِّدَاءَ اللَّهُمَّ رَبَّ هَذِهِ الدَّعْوَةِ التَّامَّةِ وَالصَّلاَةِ الْقَائِمَةِ آتِ مُحَمَّدًا الْوَسِيلَةَ وَالْفَضِيلَةَ وَابْعَثْهُ مَقَامًا مَحْمُودًا الَّذِي وَعَدْتَهُ، حَلَّتْ لَهُ شَفَاعَتِي يَوْمَ الْقِيَامَةِ
Allāhumma rabba hādhihi-d-daʿwati-t-tāmmah, wa-ṣ-ṣalāti-l-qā'imah, āti Muḥammadan-il-wasīlata wa-l-faḍīlah…
“O Allah, Lord of this perfect call and the prayer about to be established, grant Muhammad the means and the excellence, and raise him to the praised station You promised him.”
The full narration
Narrated Jabir bin `Abdullah:Allah's Messenger (ﷺ) said, "Whoever after listening to the Adhan says, 'Allahumma Rabba hadhihi-dda` watit-tammah, was-salatil qa'imah, ati Muhammadan al-wasilata wal-fadilah, wa b`ath-hu maqaman mahmudan-il-ladhi wa`adtahu' [O Allah! Lord of this perfect call (perfect by not ascribing partners to You) and of the regular prayer which is going to be established, give Muhammad the right of intercession and illustriousness, and resurrect him to the best and the highest place in Paradise that You promised him (of)], then my intercession for him will be allowed on the Day of Resurrection
Source
Ṣaḥīḥ al-Bukhārī · 614
- Agreed upon as authentic (al-Bukhārī / Muslim)