The Ancient Greek Septuagint translation of the Hebrew Bible used the word pantokrator (παντοκράτωρ) or “Ruler of All” as a translation of the second part of the Hebrew term YHWH Tz’vaót (יְהוָ֨ה צְבָא֜וֹת) or “Lord of hosts” (see here) and occasionally ʼĒl Šadạy (אֵל שַׁדַּי‎), translated in English commonly as “God Almighty.” In the deuterocanonical/apocryphal books, pantokrator might have also been used in the original writing. The New Testament uses it one time in the writings of Paul (2 Cor. 6:18) and several times in the book of Revelation (see esp. Rev. 1:8).

One of the most influential icon styles of the Orthodox church has developed from this concept: Christ Pantocrator. In this icon style, Christ is looking straight at the viewer, his right hand is typically spelling a short form of “Jesus Christ” (see the bottom of the entry on Jesus and icons for an explanation), and his left hand holds a New Testament. His head is often surrounded by a halo.

The earliest preserved icon is found in the Greek Orthodox Saint Catherine’s Monastery on Mount Sinai from the 6th century:

In order to express the two natures of Christ, the two sides of the face are not symmetrical. The right side might represent the qualities of his divinity, while his left side represents human nature. (Source )

Orthodox icons are not drawings or creations of imagination. They are in fact writings of things not of this world. Icons can represent our Lord Jesus Christ, the Virgin Mary, and the Saints. They can also represent the Holy Trinity, Angels, the Heavenly hosts, and even events. Orthodox icons, unlike Western pictures, change the perspective and form of the image so that it is not naturalistic. This is done so that we can look beyond appearances of the world, and instead look to the spiritual truth of the holy person or event. (Source )

See also LORD of hosts.