Musnad Ahmad 30:3564

Rawh narrated to us, Ibn Jurayj narrated to us, from al-‘Ala’ ibn ‘Abd al-Rahman, from his father, from Abu Hurayrah, that the Prophet, peace and blessings of Allah be upon him, said: "Yawning is from the Shaytan. So, whoever among you yawns, let him suppress it as much as he is able."