Musannaf Ibn Abi Shayba 28:19

Waki’ narrated to us, he said: Sufyan narrated to us, from ‘Ata’ ibn al-Sa’ib, from Malik ibn al-Harith, from Khaythama, he said: The Messenger of Allah (may Allah bless him and grant him peace) said: "Leadership is a door to hardship, except for whom Allah has had mercy upon."