Fausset's Bible Dictionary
Ezra 4:2; Ezra 21:22. A mound was usually raised, on which the ram was planted, to be on a level with the walls. The ram was sometimes fixed, or else joined to moveable wooden towers containing warriors. It was hung by a rope, whereby the men inside swung it forward and backward. The besieged by a double rope from the battlements tried to catch the ram, or else threw lighted torches on it.
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Fausset, Andrew R. Entry for 'Ram, Battering'. Fausset's Bible Dictionary. https://www.studylight.org/dictionaries/eng/fbd/r/ram-battering.html. 1949.