Short answers, pulled from the story.
The word angel derives from Late Greek angelos, meaning simply "messenger," which itself may have been borrowed from an oriental source related to the Greek word angaros, referring to a Persian mounted courier. Its earliest attested form is the Mycenaean Greek word preserved in Linear B syllabic script. Modern English received the word through both Old English engel and Old French angele, both rooted in Late Latin angelus.
Belief in angels is one of the Six Articles of Faith in Islam, making it a doctrinal requirement. Angels in Islam are described in the Quran as messengers with two, three, or four wings, composed of light or fire, endowed with reason, and subject to God's tests. They appear prominently in Mi'raj literature recounting Muhammad's journey through the heavens, in Islamic eschatology, and in exorcism rites where their names are engraved in talismans.
The earliest known Christian image of an angel, found in the Cubicolo dell'Annunziazione in the Catacomb of Priscilla from the mid-3rd century, shows a figure without wings. The first known representation of a winged angel appears on the Prince's Sarcophagus, attributed to the reign of Theodosius I (379-395 CE), discovered at Sarigüzel near Istanbul in the 1930s. Wings became standard in Christian art from that period onward.
Aquinas, writing in the 13th century, argued in the Summa Theologica that angels were created instantaneously by God in the Empyrean Heaven in a state of grace. They receive all knowledge at the moment of creation, grasp truth at a single glance without reasoning, and know everything in the external world but cannot read human secret thoughts dependent on free will. Each angel constitutes its own unique species, with form rather than matter serving as the principle of individuation.
The idea of angels as embodiments of goodness specifically emerged under Zoroastrian influence. Zoroastrianism conceived of the universe as a battle between Ahura Mazda, the principle of good, and the principle of evil, with holy entities called Aməša Spəṇta on the side of good. This dualistic framework introduced the notion of morally defined sides in the supernatural world, shaping how Jews and later Christians understood angels as benevolent in contrast to fallen or malevolent beings.
In Rabbinic Judaism, angels are considered inferior to humans because they have no free will of their own and can carry out only one divine command at a time. The Babylonian Talmud states that the Torah was not given to the ministering angels, understood as a recognition of human imperfection that paradoxically elevates humans. Humans who follow the Torah, resist evil instincts, and practice teshuva are regarded as preferred by God over the flawless but willless angels.