וְעָשִׂ֜יתָ לֻֽלְאֹ֣ת תְּכֵ֗לֶת עַ֣ל שְׂפַ֤ת הַיְרִיעָה֙ הָאֶחָ֔ת מִקָּצָ֖ה בַּחֹבָ֑רֶת וְכֵ֤ן תַּעֲשֶׂה֙ בִּשְׂפַ֣ת הַיְרִיעָ֔ה הַקִּ֣יצוֹנָ֔ה בַּמַּחְבֶּ֖רֶת הַשֵּׁנִֽית׃
And thou shalt make loops of blue upon the edge of the one curtain that is outmost in the first set; and likewise shalt thou make in the edge of the curtain that is outmost in the second set.
Read halakhic rulings (Jewish law) on Exodus 26:4: and classical halakhic sources.