Cassiel is an angel associated with Saturday and Saturn in early modern ceremonial-magic literature. A useful starting point is the Heptameron, which places Cassiel among the angels of Saturday. This is a source-specific tradition, rather than a description shared by every branch of Judaism or Christianity.
Cassiel in the Heptameron
In the Heptameron, the Saturday material lists Cassiel alongside Machatan and Uriel. Its associated conjuration connects the day with Saturn and uses the related forms Caphriel and Cassiel. This provides a traceable basis for Cassiel’s familiar Saturday and Saturn associations.
A ceremonial text describes the cosmology and practice of its own tradition. It does not establish that its named figures appear in biblical scripture, or that all religious communities accept its planetary correspondences.
Is Cassiel or Castiel in the Bible?
The Heptameron reference is a later source, not a biblical passage. Readers looking for scriptural angel names should start with identifiable references such as Gabriel in Daniel 8:16 and Michael in Daniel 12:1.
Do not treat Cassiel, Castiel and every similar-looking spelling as interchangeable without checking the text. A modern fictional character or a name in a secondary name list is not, by itself, evidence for an angel in the Bible.
Name variants and meanings
Cassiel and Caphriel occur in the source cited above. Longer lists of alleged variants and popular name meanings need their own references. The Heptameron passage does not establish a linguistic meaning for the name. Treat unsourced translations such as “Speed of God” cautiously.
Related reading
Browse the A–Z list of angel names, compare the orders of angels, or read the profiles of Uriel, Gabriel and Michael.
Source
Heptameron, or Magical Elements, Saturday section, in Joseph H. Peterson’s digital edition at Esoteric Archives. Consult the edition notes when comparing spellings.