Musnad Ahmad 788:272

Rawh narrated to us, he said: Sa’id narrated to us, from Qatadah, who said: Abu Burdah ibn ‘Abdullah ibn Qays narrated from his father, who said: My father said: "If you had witnessed us while we were with our Prophet, may Allah bless him and grant him peace, when the rain fell upon us, you would have thought that our scent was the scent of sheep, for our clothing was only wool."