It is narrated from Sayyiduna Thawban (may Allah be pleased with him) that the Prophet (peace and blessings be upon him) said: "The foundation of the religion is sincere goodwill (nasihah)." The Companions said: O Messenger of Allah, to whom? He (peace and blessings be upon him) said: "To Allah, the Mighty and Majestic, to His religion, to His Book, to the leaders of the Muslims, and to the Muslims in general."
This hadith is not narrated from Sayyiduna Thawban (may Allah be pleased with him) except with this chain, and Ayyub (bin Suwayd) (may Allah have mercy on him) is alone in narrating it.
Hadith Referenceالمعجم الأوسط / باب الألف / 1184
Hadith Gradingمحدثین:منكر، فيه أيوب بن سويد ضعيف
Hadith Takhrij«قال أبو حاتم الرازي: هذا حديث منكر «علل الحديث، ج 5، ص 334»» «قال الهيثمي: فيه أيوب بن سويد وهو ضعيف لا يحتج به «مجمع الزوائد ومنبع الفوائد، ج 1، ص 87»»