And the cubit on the one side … the other side refers to the two extra cubits in the length of each strip of goats’ hair material compared with the strips of the linen material. The strips of linen material were to be twenty-eight cubits long (verse 2), thus making the total first layer twenty-eight cubits wide when all the strips were joined together. This means that it would hang down on either side of the framework by only nine cubits, leaving a space of one cubit uncovered on either side. But that is the space to be covered by the second layer, which was to be thirty cubits wide (verse 8). This second layer, then, was to be placed on top of the linen fabric so that one cubit extended on either side. It was to hang over the sides of the tabernacle after it was set up. This means that the goats’ hair covering would hang down on the two sides by ten cubits, the exact height of the framework (see verse 16). In other words, it would just touch the ground, and in that way it would cover the tabernacle.
What remains in the length of the curtains refers to the two extra cubits of the goats’ hair curtains (verse 8) that will extend beyond the length of the linen curtains (verse 2), that is, thirty cubits less 28. Therefore, when all eleven of the curtains are joined together, this length actually becomes the width of the total layer. Contemporary English Version has unfortunately joined verses 12 and 13, suggesting that an extra cubit was to be folded on the sides as well as at the back.
New International Version is easier to understand than either Revised Standard Version or Good News Translation: “The tent curtains will be a cubit longer on both sides; what is left will hang over the sides of the tabernacle to cover it.” Good News Translation‘s “on each side of the length” is confusing unless it is understood to mean the length of each strip of thirty cubits. Translator’s Old Testament is clearer: “The extra cubit in the length of the curtains on each side shall hang down to cover the Shrine on both sides.” Another possible model is:
• The extra cubit [or, half-yard] in the width of this layer will hang down on both sides of the tent and will cover the tabernacle completely [or, to the ground].
Quoted with permission from Osborn, Noel D. and Hatton, Howard A. A Handbook on Exodus. (UBS Helps for Translators). New York: UBS, 1999. For this and other handbooks for translators see here .