τετράδιον

a group of four soldiers

Definition

The Greek word τετράδιον (tetradion) refers to a 'quaternion' or a group of four. In its sole New Testament occurrence, it specifically denotes a squad of four soldiers, likely functioning as a single guard unit. This military application is seen in Acts 12:4, where Herod Agrippa I places Peter under the guard of four squads of soldiers (τεσσάρων τετραδίων στρατιωτῶν). The term inherently emphasizes the number four as the basic organizational unit for this duty.

Biblical Usage

This word is used only once in the New Testament, in Acts 12:4. It describes the specific military arrangement for guarding the apostle Peter in prison. The text states Peter was delivered to four quaternions of soldiers, indicating a rotation of four squads, each consisting of four men, to guard him in shifts (likely corresponding to the four watches of the night). This precise terminology highlights the high-security measures taken by Herod.

Etymology

τετράδιον is a diminutive noun derived from the Greek word τέτταρες (tettares), meaning 'four.' The -διον suffix forms a noun indicating a small group or unit. Thus, its core meaning is 'a little set of four' or 'a quartet.' It is related to the adjective τετράς (tetras), which also means a group of four.

Semantic Range

While the word itself is a mundane military term, its use in Acts 12:4 is theologically significant. It underscores the seemingly insurmountable human power arrayed against Peter—a detail that makes his miraculous, angelic deliverance in Acts 12:6-11 all the more dramatic. It highlights God's sovereign power to overcome any human restraint for the sake of His church and the spread of the gospel.

In the Roman military system, a quaternion was a common unit for guard duty, especially for important prisoners. A squad of four soldiers allowed for continuous watchfulness, with two likely chained to the prisoner and two guarding the doors (as implied in Acts 12:6). This practice ensured security through constant supervision and rotation. The term reflects the precise, organized nature of Roman military administration.

σπεῖρα (speira, G4686) — a larger military cohort or band of soldiers, typically 600 men. φυλακή (phylakē, G5438) — a general term for guard, watch, or prison, focusing on the function rather than the specific number of personnel.

Word Details

Scripture References