Exodus 28:31
Make the robe that is worn with the ephod entirely of violet material.
Exodus 28:4
The clothes they will make are as follows: a breastplate, an ephod and the robe that is worn with it, another specially woven linen robe, the chief priest's turban, and a cloth belt. They will make these holy clothes for your brother Aaron and his sons so that they will be able to serve me as priests.
Exodus 28:28
Then the breastplate should be fastened by its rings to the rings of the ephod with a violet cord. Attach it just above the belt of the ephod. This will hold the breastplate in place.
Exodus 39:22-26
They made the robe that is worn with the ephod. It was woven entirely of violet yarn.
Leviticus 8:7
He clothed Aaron with the embroidered tunic and tied the sash around him. He also dressed him in the linen robe that is worn with the ephod. He fastened the ephod to it.