Tekhelet is a highly valued dye described as either "sky blue", or "light blue", that held great significance in ancient Mediterranean civilizations. In the Hebrew Bible and Jewish tradition, tekhelet was used to color the clothing of the High Priest, the tapestries in the Tabernacle, and the tzitzit (fringes) attached to the corners of four-cornered garments, including the tallit. The mention of tekhelet is particularly notable in the third paragraph of the Shema, referencing Numbers 15:37–41.
A set of Tzitzit, four "tassels" or fringes with sky blue threads produced from a Hexaplex trunculus-based dye – tied according to the opinion of the Sefer ha-Chinuch.
The national flag of Israel
Murex shells from the Iron Age II period (10th-7th centuries BCE) with ancient remains of purple on the shards seen on the right.
Aaron wearing a robe, as depicted in the 3rd century when tekhelet was still worn
According to the Hebrew Bible, the tabernacle, also known as the Tent of the Congregation, was the portable earthly dwelling used by the Israelites from the Exodus until the conquest of Canaan. Moses was instructed at Mount Sinai to construct and transport the tabernacle with the Israelites on their journey through the wilderness and their subsequent conquest of the Promised Land. After 440 years, Solomon's Temple in Jerusalem superseded it as the dwelling-place of God.
Model of the tabernacle in Timna Valley Park, Israel
The tabernacle, engraving from Robert Arnauld d'Andilly's 1683 translation of Josephus.
Tabernacle Tent dimensions according to the Book of Exodus
Tabernacle Tent and Courtyard dimensions according to the Book of Exodus