Weak
graded by Al-Albani
Mishkat al-Masabih 1445
وَعَنْ عَطَاءٍ مُرْسَلًا أَنَّ النَّبِيَّ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ كَانَ إِذَا خَطَبَ يَعْتَمِدُ عَلَى عنزته اعْتِمَادًا. رَوَاهُ الشَّافِعِي
‘Ata’ told in mursal form that when the Prophet preached he would lean on his javelin. Shafi'i transmitted it.
Cited in Mishkat al-Masabih (No. 1445).