Musnad Ahmad 834:5

Waki’ and Ibn Ja’far narrated to us, they said: Kahmas ibn al-Hasan narrated to us, from Ibn Buraydah. Ibn Ja’far said in his narration: Ibn Buraydah informed me, from ‘Abdullah ibn Mughaffal, he said: The Messenger of Allah (peace and blessings of Allah be upon him) said: "Between every two calls (Adhan and Iqamah) is a prayer," three times, "for whoever wishes."