Sayyiduna Abdullah bin Mas'ud (may Allah be pleased with him) said, regarding the saying of Allah Almighty: "And let them not display their adornment" [Surah al-Nur: 31]: "Adornment means bracelets, armlets, anklets, 'al-adab' (an unclear word, probably a copyist's error), earrings and necklaces; and what appears of it means the (outer) garments and the cloak."
Hadith Referenceالمعجم الكبير للطبراني / باب العين / 9085