### Core Meaning & Semantic Range
The Greek word τετράδιον (tetrádion `{{G5069}}`) is a neuter noun derived from a presumed root related to τέσσαρες (tessares `{{G5064}}`), meaning "four." Its core meaning denotes a group or unit of four. In its specific usage within the biblical text, it refers to a "quaternion," which is a military squad consisting of four Roman soldiers. This term precisely describes a common organizational unit within the Roman army, emphasizing a specific numerical grouping dedicated to a particular task, often guard duty. The semantic range is therefore quite narrow, focused on this military application of the number four.
### Biblical Occurrences & Contextual Analysis
The term τετράδιον (tetrádion `{{G5069}}`) appears only once in the New Testament, specifically in [[Acts 12:4]]. The context is the intense persecution of the early church by King Herod Agrippa I, who had already executed James and then proceeded to arrest Peter. The text states that Herod "put him in prison, delivering him over to four quaternions of soldiers to guard him, intending after the Passover to bring him out to the people."
This detail is highly significant. The deployment of "four quaternions" means that Peter was guarded by a total of sixteen soldiers (4 groups of 4). This substantial guard detail likely operated in shifts, with four soldiers on duty at any given time (two perhaps inside the cell, two outside, or chained to the prisoner). This level of security underscores the extreme measures taken by Herod to prevent Peter's escape, especially given the previous miraculous release of apostles from prison (cf. [[Acts 5:19]]). The meticulousness of the Roman guard system, reflected in this precise numerical designation, highlights the formidable human obstacle Peter faced. It sets the stage for the dramatic divine intervention that follows, where God's power utterly transcends even the most stringent human security.
### Related Words & Concepts
The most directly related word is τέσσαρες (tessares `{{G5064}}`), the cardinal number "four," from which τετράδιον is derived. This connection emphasizes the numerical precision inherent in the term.
Beyond direct etymology, τετράδιον relates to broader concepts within the New Testament:
* **Roman Military Organization:** It provides a glimpse into the structured and disciplined nature of the Roman army, which was the dominant military and political power of the time.
* **Imprisonment and Custody:** The word is used in the context of securing a prisoner, linking it to themes of human confinement (δεσμός `{{G1199}}`, φυλακή `{{G5438}}`) and the role of guards (φρουρέω `{{G5432}}`).
* **Divine Sovereignty vs. Human Power:** The presence of such a strong guard serves as a foil to God's miraculous intervention, highlighting the ultimate futility of human efforts to thwart divine will.
### Theological Significance
While τετράδιον itself is a descriptive military term, its singular appearance in [[Acts 12:4]] carries profound theological weight by setting the stage for a powerful demonstration of divine power. The mention of "four quaternions" emphasizes the overwhelming human force arrayed against Peter, making his subsequent liberation all the more miraculous.
Theologically, this detail underscores several key points:
1. **God's Omnipotence:** The human attempt to secure Peter with sixteen soldiers, under strict Roman discipline, represents the apex of human security. Yet, this formidable barrier is effortlessly overcome by a single angel of the Lord ([[Acts 12:7-10]]). This highlights God's absolute power and His ability to deliver His servants from any human constraint.
2. **Divine Protection of the Church:** Despite severe persecution and human efforts to suppress the nascent Christian movement, God actively intervenes to protect His key leaders and ensure the continuation of His work. The τετράδιον serves as a stark reminder of the opposition, making God's deliverance all the more evident as a testament to His care for His people.
3. **Contrast Between Earthly and Heavenly Authority:** Herod's authority, backed by military might, is shown to be utterly subordinate to God's heavenly authority. The meticulous planning of the "quaternions" by human power is rendered meaningless by divine decree.
### Summary
The Greek word τετράδιον (tetrádion `{{G5069}}`) precisely denotes a "quaternion" or a squad of four Roman soldiers. Its sole biblical occurrence in [[Acts 12:4]] describes the extensive guard placed upon the Apostle Peter by Herod Agrippa I, involving four such quaternions, totaling sixteen soldiers. Far from being a mere historical detail, this specific numerical designation serves a crucial theological purpose. It meticulously portrays the formidable human security measures taken to imprison Peter, thereby magnifying the miraculous nature of his subsequent divine liberation. The τετράδιον thus functions as a powerful literary and theological device, highlighting the stark contrast between the limitations of human power and the limitless sovereignty of God, who effortlessly delivers His servants from even the most secure human confinement.