The Messenger of Allah ﷺ said, "Whichever men of the Jews you come across, kill them." So Muhaysa pounced on Shabiba, a Jewish merchant who used to associate with them, and killed him. Huwaysa at that time had not yet accepted Islam, and he was older than Muhaysa. When Muhaysa killed the man, Huwaysa began to strike him, saying, "Enemy of Allah, by Allah, much of the fat in your belly comes from his wealth."
حدثنا مصرف بن عمرو حدثنا يونس قال ابن إسحق حدثني مولى لزيد بن ثابت
أن رسول الله ﷺ قال من ظفرتم به من رجال يهود فاقتلوه فوثب محيصة على شبيبة رجل من تجار يهود كان يلابسهم فقتله وكان حويصة إذ ذاك لم يسلم وكان أسن من محيصة فلما قتله جعل حويصة يضربه ويقول يا عدو الله أما والله لرب شحم في بطنك من ماله
No references are available.
Source references, its isnad is daif. Bayhaqi narrated it in Dalail, 3/200, through the hadith of Ibn Ishaq via the same chain. It is also found in Aqd Tammam fi Takhrij Sirah Ibn Hisham, 2/58. The freedman of Zayd is of unverified reliability, see the previous hadith, and the daughter of Muhaysah is unknown.