(56) باب بَيْنَ كُلِّ أَذَانَيْنِ صَلاَةٌ
Abdullah b. Mughaffal reported Allah's Messenger (ﷺ) 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.
Reference: Sahih Muslim 838 a
In-book reference: Book 6, Hadith 368
USC-MSA web (English) reference(deprecated numbering scheme): Book 4, Hadith 1822