Yahya related to me from Malik from Hisham ibn Urwa that his father said to him, "When you are on a journey you can, if you wish, call the adhan and the iqama, or, if you wish, the iqama and not the adhan."

Yahya said that he heard Malik say, "There is no harm in a man calling the adhan while riding."
Muwatta Malik Book 3, Hadith 13
← Previous Hadith Yahya related to me from Malik from Nafi that on a journey Abdullah ibn Umar did no more than the iqama, except for subh, when he called both the adhan and the iqama. Abdullah ibn Umar used to say, "The adhan is for an imam whom people join ."

Muwatta Malik Book 3, Hadith 12 Next Hadith → Yahya related to me from Malik from Yahya ibn Said that Said ibn al-Musayyab used to say, "Whoever prays on waterless, desolate land - an angel prays on his right and an angel prays on his left. When he calls both the adhan and the iqama for the prayer, or calls out the iqama, angels like mountains pray behind him."

Muwatta Malik Book 3, Hadith 14