Musannaf Ibn Abi Shaybah 38549 — the first to do a thing, and who did

Mujahid said: The Messenger of Allah (peace and blessings be upon him) met a people among whom a camel-driver was chanting the huda (camel song), but when they saw the Messenger of Allah (peace and blessings be upon him), he fell silent. The Prophet (peace and blessings be upon him) asked: Who are these people? He was told that they were from the tribe of Mudar. The Prophet (peace and blessings be upon him) said: I too am from Mudar. Then he said: Why has your camel-driver fallen silent? They said: O Messenger of Allah! We are the first of the Arabs to chant the huda. The Prophet (peace and blessings be upon him) said: How so? They said: A man of our people, whom they named, was away with his camels in the days of spring. He sent his slave with the camels, and the slave was late. Then the slave came, and the man began to beat him with a stick on his hand. The slave set off saying: "Wa yadah! Wa yadah!" (Alas my hand, alas my hand). Hearing these words the camels began to move quickly and became lively. The man said: Keep saying this, keep saying this. After that the huda became customary among the people.