O Dog, Son of a Dog!
“Do not insult one another by (offensive) nicknames” (Qurʾān, 49: 11)
بسم الله الرحمن الرحیم
The great Shāfiʿī scholar Shaykh Tāj al-Dīn al-Subkī (d. 771/1370) writes in al-Tarshīḥ:
“One day, I was with a group of people in the courtyard of our house. A dog passed us with water dripping from him which was about to touch our clothes. So I rebuked him and said, “O dog, the son of a dog.” The Shaykh Imam [referring to his father Shaykh al-Islam Taqī al-Dīn al-Subkī, d. 756/1355] was listening to us from the inside. When he came out, he said: “Why did you humiliate him?” So I said, “I did not say but the truth. Is he not a dog the son of a dog?” He replied, “He is for sure, except that you uttered the words as an insult and to humiliate, and this is not appropriate.” So I said, herein is a beneficial point: Any creation [of Allah] should not be addressed by their inherent characteristics, unless the words are uttered in a non-demeaning manner.
From: Islamic Portal