Charles Ellicott Commentary Exodus 25:4

"and blue, and purple, and scarlet, and fine linen, and goats` [hair]," — Exodus 25:4 (ASV)

And blue, and purple, and scarlet. —The colours intended are probably: a dark blue produced from indigo, which was the only blue known to the Egyptians; a purplish crimson derived from the murex trunculus, the main source of the “Tyrian dye” of the ancients; and a scarlet furnished by the coccus ilicis, or cochineal insect of the holm oak. This scarlet was largely employed in antiquity, though now superseded by the brighter tint obtained from the coccus cacti of Mexico. Linen yarn of the three colours mentioned seems to have been what the people were asked to furnish (Exodus 35:25; Exodus 39:1).

Fine linen —i.e., white thread spun from flax, which is found to be the material of almost all the Egyptian dresses, mummy cloths, and other undyed fabrics. It is yellowish-white, soft, and wonderfully fine and delicate. (See Wilkinson in Rawlinson’s Herodotus, vol. ii., p. 233).

Goats’ hair. —The covering of an Arab tent is to this day almost always of goats' hair. An excellent fabric is woven from the soft inner hair of the Syrian goat, and a coarse one from the outer coat of the animal. Yarn of goats' hair was to be offered, so that from it the first of the three outer coverings of the Tabernacle might be produced (Exodus 26:7–14).