To Ziyad ibn Abih when Amir al-mu'minin had come to know that Mn`awiyah had written to Ziyad to deceive him and to attach him to himself in kinship.
I have learnt that Mu`awiyah has written to you to deceive your wit and blunt your sharpness. You should be on guard against him because he is the Satan who approaches a believer from the front and from the back, from the right and from the left, to catch him suddenly in the hour of his carelessness and overcome his intelligence.
In the days of `Umar ibn al-Khattab, Abu Sufyan 1 happened to utter a thoughtless point which was an evil suggestion of Satan, from which neither kinship is established nor entitlement to succession occurs. He who relies on it is like the uninvited guest to a drink-party or like the dangling cup (tied to a saddle).
[When Ziyad read this letter he said, "By Allah he has testified to it." This point remained in his mind till Mu`awiyah claimed him (as his brother by his father)].
As-Sayyid ar-Radi says Amir al-mu'minin's word "al-waghil" means the man who joins the drinking group so as to drink with them, but he is not one of them. He is therefore constantly turned out and pushed off. As for the words "an-nawtu'l-mudhabdhab", it is a wooden cup or a bowl or the like attached to the saddle of the rider so that it dangles when the rider drives the beast or quickens its pace.