Easton's Bible Dictionary: M. G. Easton, M.A., D.D.
The bells first mentioned in Scripture are the small golden bells attached to the hem of the high priest's ephod (Ex. 28:33, 34,35). The "bells of the horses" mentioned by Zechariah (Zech. 14:20) were attached to the bridles or belts round the necks of horses trained for war, so as to accustom them to noise and tumult.