Musannaf Ibn Abi Shayba 3:3470

Muhammad ibn Fudayl narrated to us, from ‘Ata’ ibn al-Sa’ib, who said: Two Eids coincided on one day. Al-Hajjaj stood up during the first Eid and said: "Whoever wishes to pray with us, let him pray, and whoever wishes to leave, let him leave, and there is no blame." Abu al-Bakhtari and Maysarah said: "What is wrong with him? May Allah kill him! From where did he stumble upon this?"