The Bible uses the terms מלאך אלהים (mal’āk̠ Elohim ’ĕlōhîm; messenger of God), מלאך יהוה (mal’āk̠ YHWH; messenger of the Lord), בני אלהים (bənē Elohim ’ĕlōhîm; sons of God) and הקודשים (haqqôd̠əšîm; the holy ones) to refer to beings traditionally interpreted as angels. Later texts use other terms, such as העליונים (hā‘elyônîm; the upper ones).
The term מלאך (Malak mal’āk̠) is also used in the Tanakh; a similar term, ملائكة (malā’ikah), is used in the Qur'an. The Greek and Hebrew words, depending on the context may refer either to a human messenger or a supernatural messenger. The human messenger could possibly be a prophet or priest, such as Malachi, "my messenger", and the Greek superscription that the Book of Malachi was written "by the hand of his messenger" ἀγγήλου angḗlou. Examples of a supernatural messenger are the "Malak YHWH," who is either a messenger from God, an aspect of God (such as the Logos), or God himself as the messenger (the "theophanic angel.")
Scholar Michael D. Coogan notes that it is only in the late books that the terms "come to mean the benevolent semidivine beings familiar from later mythology and art." Daniel is the first biblical figure to refer to individual angels by name, mentioning Gabriel (God's primary messenger) in Daniel 9:21 and Michael (the holy fighter) in Daniel 10:13. These angels are part of Daniel's apocalyptic visions and are an important part of all apocalyptic literature. Coogan explains the development of this concept of angels:
"In the postexilic period, with the development of explicit monotheism, these divine beings—the 'sons of God' who were members of the Divine Council— were in effect demoted to what are now known as 'angels', understood as beings created by God, but immortal and thus superior to humans." This conception of angels is best understood in contrast to demons and is often thought to be "influenced by the ancient Persian religious tradition of Zoroastrianism, which viewed the world as a battleground between forces of good and forces of evil, between light and darkness." One of these is hāšāṭān, a figure depicted in (among other places) the Book of Job.
Philo of Alexandria identifies the angel with the Logos as far as the angel is the immaterial voice of God. The angel is something different than God Himself, but is conceived as God's instrument.
In post-Biblical Judaism, certain angels took on particular significance and developed unique personalities and roles. Though these archangels were believed to rank among the heavenly host, no systematic hierarchy ever developed. Metatron is considered one of the highest of the angels in Merkabah and Kabbalist mysticism and often serves as a scribe; he is briefly mentioned in the Talmud and figures prominently in Merkabah mystical texts. Michael, who serves as a warrior and advocate for Israel (Daniel 10:13), is looked upon particularly fondly. Gabriel is mentioned in the Book of Daniel (Daniel 8:15–17), the Book of Tobit, and briefly in the Talmud, as well as in many Merkabah mystical texts. There is no evidence in Judaism for the worship of angels, but there is evidence for the invocation and sometimes even conjuration of angels.