Sayyiduna Ismah (may Allah be pleased with him) said: The Messenger of Allah (peace and blessings be upon him) had a spear that would be carried in front of him (peace and blessings be upon him), and when he (peace and blessings be upon him) prayed, he would plant it in front of himself.
Hadith Referenceالمعجم الكبير للطبراني / باب العين / 14557