“After being released from his first Roman imprisonment (cf. Acts 28:30), Paul revisited several of the cities in which he had ministered, including Ephesus. Leaving Timothy behind there to deal with problems that had arisen in the Ephesian church, such as false doctrine (1:3–7; 4:1–3; 6:3–5), disorder in worship (2:1–15), the need for qualified leaders (3:1–14), and materialism (6:6–19), Paul went on to Macedonia, from where he wrote Timothy this letter to help him carry out his task in the church (cf. 3:14,15).”
– John MacArthur