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 (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.
Bell
On the hem of the high priest’s robe, golden bells alternate with pomegranates of blue, purple and scarlet: “a golden bell and a pomegranate, a golden bell and a pomegranate” (Exodus 28:34). The text says the sound is to be heard when he goes into the holy place (Exodus 28:35). Zechariah looks ahead to a day when even “the bells of the horses” will carry the words HOLINESS UNTO THE LORD (Zechariah 14:20), so that ordinary things become sacred. Exodus 28 describes the priest’s whole outfit.
3 verses
Exodus
And beneath upon the hem of it thou shalt make pomegranates of blue, and of purple, and of scarlet, round about the hem thereof; and bells of gold between them round about:
A golden bell and a pomegranate, a golden bell and a pomegranate, upon the hem of the robe round about.
Zechariah
In that day shall there be upon the bells of the horses, HOLINESS UNTO THE LORD; and the pots in the LORD'S house shall be like the bowls before the altar.
From Easton's Bible Dictionary
Matthew George Easton, 1897