The name "Sealtiel" is from Hebrew Shealtiel, "prayer of God." He does not appear in canonical scripture, but in the 5th- or 6th-century Conflict of Adam and Eve he and another angel are sent to rescue Adam and Eve from the mountaintop where Satan had planned to cast them to their death, and from there he entered into Orthodox and Roman Catholic lore.1
According to his Wikipedia article, Sealtiel is believed by some to be the angel in Revelation 8:3 who "stood before the altar, having a golden thurible, a censer hanging from a chain so it can be swung and there was given to him much incense, that he should offer of the prayers of all saints upon the golden altar, which is before the throne of God." This identification is reflected in images of Sealtiel, where his attribute is a thurible, a censer hanging from a chain so it can be swung as in the first picture at right.
In the second picture at right Sealtiel holds a banderole with the Latin words oratio dei, "prayer of God." This is the meaning of his name in Hebrew.
Prepared in 2021 by Richard Stracke, Emeritus Professor of English, Augusta University.