The Hebrew word bad refers to linen cloth or linen thread — specifically the fine white linen used in sacred garments. It is the material of the high priest's undergarments, the linen ephod, and the angelic figures described in Daniel and Ezekiel.
Linen in the Old Testament is consistently associated with purity, priestly service, and divine holiness. The high priest wore bad garments on the Day of Atonement — a deliberate stripping down to simple white linen rather than golden vestments, symbolizing humble approach before God. The angelic figure in Daniel 10:5 is clothed in linen, representing heavenly purity. Revelation 19:8 declares that the fine linen of the bride of Christ represents 'the righteous acts of God's holy people.' The material itself becomes a theological symbol: those who draw near to God must be clothed in purity.