Sayyiduna Anas (may Allah be pleased with him) states: The Prophet (peace and blessings be upon him) forbade sitting in the manner of iq'a' and tawarruk during the prayer.
Bazzar recorded it from his teacher Harun bin Sufyan, and I have not found anyone who mentions him; the rest of its narrators are the narrators of the Sahih.
Hadith Referenceمجمع الزوائد ومنبع الفوائد / كتاب الصلاة / 2467