Imam Bukhari narrates: Ishaq al-Wasiti narrated to us, he said: Khalid narrated to us from al-Jurairi from Ibn Buraidah from Abdullah bin Mughaffal al-Muzani that
the Messenger of Allāh ﷺ said three times: Between every two Adhans there is a prayer. This is for whoever wishes to pray.
حَدَّثَنَا إِسْحَاقُ الْوَاسِطِيُّ، قَالَ حَدَّثَنَا خَالِدٌ، عَنِ الْجُرَيْرِيِّ، عَنِ ابْنِ بُرَيْدَةَ، عَنْ عَبْدِ اللَّهِ بْنِ مُغَفَّلٍ الْمُزَنِيِّ، أَنَّ رَسُولَ اللَّهِ صلى الله عليه وسلم قَالَ " بَيْنَ كُلِّ أَذَانَيْنِ صَلاَةٌ ـ ثَلاَثًا ـ لِمَنْ شَاءَ ".
Reference: Sahih Al Bukhari 624