Sayyiduna Ali (may Allah be pleased with him) narrates: The Prophet (peace and blessings be upon him) said: "Were it not that I feared I would burden my Ummah with hardship, I would have commanded them to use the siwak with every ablution."
Imam al-Tabarani recorded this report in al-Mu'jam al-Awsat; its chain contains a narrator, Ibn Ishaq, who is thiqah (trustworthy) but a mudallis; in this report he has explicitly stated that he heard it directly (tahdith), and its chain is hasan (good).
Hadith Referenceمجمع الزوائد ومنبع الفوائد / كتاب الطهارة / 1117
Hadith Gradingمحدثین:إسنادہ حسن۔
Hadith Takhrij«أخرجه المعجم الأوسط للطبراني برقم: 1260، وأخرجه شرح معاني الآثار برقم: 234»