Sahih al-Bukhari 668

Narrated `Abdullah bin Al-Harith:Ibn `Abbas addressed us on a (rainy and) muddy day and when the Mu'adh-dhin said, "Come for the prayer" Ibn `Abbas ordered him to say, "Pray in your homes." The people began to look at one another with surprise as if they did not like it. Ibn `Abbas said, "It seems that you thought ill of it but no doubt it was done by one who was better than I (i.e. the Prophet). It (the prayer) is a strict order and I disliked to bring you out." Ibn `Abbas narrated the same as above but he said, "I did not like you to make you sinful (in refraining from coming to the mosque) and to come (to the mosque) covered with mud up to the knees