Sunan Ibn Majah
1162
Sahih+3

It was narrated that ‘Abdullah bin Mughaffal said:“The Prophet of Allah (ﷺ) said: ‘Between every two Adhans there is a prayer.’ He said it three times, and on the third time he said, ‘For those who wish.’”

SahihAl-Albani
SahihMuhammad Fouad Abd al-Baqi