The Messenger of Allah ﷺ said, "He is the worst of the three if he acts as his parents acted," meaning the child born of adultery.
حدثنا أسود بن عامر قال حدثنا إسرائيل قال حدثنا إبراهيم بن إسحاق عن إبراهيم بن عبيد بن رفاعة
قال رسول الله ﷺ هو شر الثلاثة إذا عمل بعمل أبويه يعني ولد الزنا
No references are available.
Its isnad is daif, because of Ibrahim bin Ishaq. The correct view is that he is Ibrahim bin Fadl Abu Ishaq, as was concluded to be the more likely view in Tajil. Haythami said in 8/257, "I do not know him." Abu Dawud narrated it, 4/29, no. 3963.