الْمَجْدُ بَيْنَ ثَوْبَيْهِ
Glory is between his two garments; that is, the wearer is glorious.
Syntax: «المجد» is the subject of the nominal sentence; «بين» is an adverbial expression followed by the genitive «ثوبيه», and the locative phrase serves predicatively. The attached pronoun refers to the wearer.
Glory is not being attributed to the fabric as such. Its location between the garments implies glory possessed by the wearer.