Exodus 28:31
"You shall make the robe of the ephod all of blue.
Exodus 28:4
These are the garments that they shall make: a breastpiece, an ephod, a robe, a coat of checker work, a turban, and a sash. They shall make holy garments for Aaron your brother and his sons to serve me as priests.
Exodus 28:28
And they shall bind the breastpiece by its rings to the rings of the ephod with a lace of blue, so that it may lie on the skillfully woven band of the ephod, so that the breastpiece shall not come loose from the ephod.
Exodus 39:22-26
He also made the robe of the ephod woven all of blue,
Leviticus 8:7
And he put the coat on him and tied the sash around his waist and clothed him with the robe and put the ephod on him and tied the skillfully woven band of the ephod around him, binding it to him with the band.