Exodus 26:3-5

King James Version

³ The five curtains shall be coupled together one to another; and other five curtains shall be coupled one to another.

⁴ And thou shalt make loops of blue upon the edge of the one curtain from the selvedge in the coupling; and likewise shalt thou make in the uttermost edge of another curtain, in the coupling of the second.

⁵ Fifty loops shalt thou make in the one curtain, and fifty loops shalt thou make in the edge of the curtain that is in the coupling of the second; that the loops may take hold one of another.