The Tabernacle is described with some of the most detailed information ever written on a specific topic in the Bible. One of the themes associated with the Tabernacle is the use of the color blue. We are told in Exodus 25:4 that the Israelites donated blue, purple and scarlet thread for the Tabernacle.
Blue thread was used in many parts of the Tabernacle (cf. Ex. 26:1; 26:31; 26:36; 27:16; Num. 4:6,7,9,11,12), the High Priest garments (cf. Ex. 28:5,6,31,33; 28:15,28,37), and lastly tassels of blue were attached to the Israelites garments (Num. 15:38). The Lord explained the reason for these blue tassels “And you shall have the tassel, that you may look upon it and remember all the commandments of the LORD and do them” (Num. 15:39).
Recently a “scholar, Zvi C. Koren, a professor specializing in the analytical chemistry of ancient colorants, says he has identified the first known physical sample of tekhelet [blue color] in a tiny, 2,000-year-old patch of dyed fabric recovered from Masada, King Herod’s JudeanDesert fortress” according to the New York Times (see photo). The test results show the blue to be a shade of indigo and not the light sky blue used today in Jewish garments. “Determining what exactly tekhelet would have looked like in its day has been the subject of conjecture and curiosity among rabbis, religious commentators and scientists for centuries; it is considered the most important of the three ritual colors cited in the Bible. The other two are argaman, a reddish purple, and shani, known as scarlet.”
Just as God said the tassels were to remind the Israelites of obeying the commandments we, like David, can pray each day for the Lord to “Open my eyes, that I may see wondrous things from Your law” (Ps. 119:18).
Picture from here