The Greek ephistēmi (G2186) means to stand near, arrive suddenly, or come upon someone. In Luke-Acts it is the characteristic verb for angelic appearances: the angel of the Lord 'appeared' (ephistēmi) to the shepherds (Luke 2:9), to the disciples at the tomb (Luke 24:4), to Peter in prison (Acts 12:7). Paul uses it for urgent apostolic ministry: 'Preach the word; be prepared in season and out of season' — 'be prepared' translates epistethi (2 Timothy 4:2), the imperative of ephistēmi: 'stand at your post!'
Ephistēmi creates a theology of divine suddenness. God breaks into human situations without warning: angels appear, the Lord comes, the Spirit arrives. Paul's charge in 2 Timothy 4:2 uses the same verb to charge Timothy to 'stand at his post' in preaching — matching the readiness of the divine messenger with the readiness of the human one. The Christian minister is to be as consistently present and ready as an angel: not waiting for convenient moments but standing ready in all seasons. The Day of the Lord itself comes like a thief — suddenly, without warning (1 Thessalonians 5:3: 'sudden destruction comes upon them').