Hazrat Mahdi (as) will use his hand to emphasize what he is saying

Hazrat Mahdi (as) will use his hands when he talks; he will move his hand as he wishes to emphasize what he is saying and that people will see those motions:

Hazrat Mahdi (as) will STRIKE HIS LEFT KNEE WITH HIS RIGHT HAND when he speaks slowly and steadily. (Jalaluddin as-Suyuti, Kıyamet alametleri, Olum ve Dirilis [Portents of the Judgment Day, Death and Resurrection], p. 174)