Musnad Ahmad 577:2

'Ali ibn 'Ayyash narrated to us, Isma'il ibn 'Ayyash narrated to us, he said: Yahya ibn Sa'id narrated to me, he said: Muhammad ibn Yahya ibn Habban informed me, from Nu'aym ibn al-Nahham, he said: "The call for the morning prayer was made on a cold day while I was in the wrap of my wife. I said: 'I wish the caller had said: Whoever stays behind, there is no blame upon him.' Then the caller of the Prophet, may Allah bless him and grant him peace, called out at the end of his adhan: 'And whoever stays behind, there is no blame upon him.'"