The bells first mentioned in Scripture are the small golden bells attached to the hem of the high priest's ephod ( Exodus 28:33 Exodus 28:34 Exodus 28:35 ). The "bells of the horses" mentioned by ( Zechariah 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.

These dictionary topics are from
M.G. Easton M.A., D.D., Illustrated Bible Dictionary, Third Edition,
published by Thomas Nelson, 1897. Public Domain, copy freely.