How Angels Found their Wings | History Today:
The angels of the Bible were not winged. (The winged Cherubim and Seraphim are figures derived from the Near Eastern tradition of winged zoomorphic guardian figures and are not angels since they perform none of the angelic functions.) In fact, in the Old Testament angels are often not clearly distinguished from humans at all. The New Testament letter to the Hebrews recommends: ‘Do not forget to show hospitality to strangers, for by so doing some people have shown hospitality to angels without knowing it.’ When angels are clearly identified in the New Testament, they are distinguished from ordinary humans by markers first found in Old Testament books, such as gleaming white robes, or a countenance like lightning – but no wings.