Origins
The word 'apostle' encodes one of early Christianity's most consequential acts of linguistic appropriation. Greek 'apostolos' (ἀπόστολος) was not a religious term. In classical and Hellenistic Greek, it belonged to the vocabulary of naval expeditions and commercial dispatches. An 'apostolos' was a fleet sent on a mission, or the admiral commanding such a fleet, or more generally any envoy dispatched with authority to act on behalf of the sender. The word derived from 'apostellein' (ἀποστέλλειν) — to send away, to dispatch — itself composed of 'apo-' (away from) and 'stellein' (to send, to set in order, to equip).
The deeper root of 'stellein' reaches back to Proto-Indo-European *stel-, meaning to put or place, which also produced English 'stall' and German 'stellen' (to place). The original sense was concrete and physical: arranging, positioning, equipping. Greek extended it to the act of dispatching — equipping and sending forth.
The transformation of 'apostolos' from a secular to a sacred term occurred in the Jewish Greek-speaking community before Christianity. The Greek translation of the Hebrew Bible (the Septuagint) occasionally used 'apostolos' and its verb form to translate the Hebrew 'shalach' (to send), particularly in contexts where God dispatches a prophet or messenger. This usage established a precedent: a person sent by divine authority could be called an apostolos.
Greek Origins
The New Testament writers — composing in Greek — adopted 'apostolos' as the standard title for the twelve men Jesus chose as his inner circle of disciples and commissioned to spread his teaching. The Gospels record Jesus selecting the Twelve and naming them 'apostoloi' — those sent forth. The term distinguished them from the broader group of followers ('mathētai,' disciples or learners) by emphasizing their commission: they were not merely students but authorized representatives, sent with the sender's full authority.
Paul of Tarsus extended the term further. Though not one of the original Twelve, Paul vigorously claimed the title 'apostolos' on the grounds that the risen Christ had personally commissioned him. His letters contain some of the most impassioned defenses of apostolic authority in the New Testament, and his successful assertion of the title helped transform 'apostle' from a designation of the Twelve into a broader category of divinely commissioned leadership.
The word entered Latin as 'apostolus,' a direct transliteration from Greek, and passed into virtually every European language through the Latin of the Church. Old English borrowed it as 'apostol,' one of the earliest Christian Latin loanwords in the language. The modern English spelling with '-le' reflects a common Middle English adjustment of Latin '-olus' endings.
Cultural Impact
In post-biblical English, 'apostle' developed two distinct trajectories. In religious usage, it retained its specific New Testament sense while also being applied to later missionaries who converted entire nations — Saint Patrick is the Apostle of Ireland, Saint Boniface the Apostle of Germany. In secular usage, it came to mean any zealous advocate or pioneer: 'an apostle of free trade,' 'an apostle of nonviolence.' This secular sense preserves the original Greek implication of someone dispatched with a mission, stripped of its theological content.
The related word 'epistle' shares the same root 'stellein' but with the prefix 'epi-' (to, upon) rather than 'apo-' (away from). An epistle is something sent to someone; an apostle is someone sent away from a source of authority. The two words, standing side by side in English, map the two directions of the same act of communication: the message that arrives and the messenger who departs.