Adam Clarke on Genesis 27:15

Goodly raiment - Mr. Ainsworth has a sensible note on this place. "The priest in the law had holy garments to minister in, Exo 28:2-4, which the Septuagint there and in this place term την στολην, The robe, and στολην ἁγιαν, the holy robe. Whether the first-born, before the law, had such to minister in is not certain, but it is probable by this example; for had they been common garments, why did not Esau himself, or his wives, keep them? But being, in all likelihood, holy robes, received from their ancestors, the mother of the family kept them in sweet chests from moths and the like, whereupon it is said, Gen 27:27, Isaac smelled the smell of his garments." The opinion of Ainsworth is followed by many critics.