Exodus 28:28

28And 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 28:31

31 a“You shall make the robe of the ephod all of blue.

Numbers 15:38

38Speak to the people of Israel, and tell them to bmake tassels on the corners of their garments throughout their generations, and to put a cord of blue on the tassel of each corner.
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