he begins to sound his trumpet: See 1 Corinthians 15:51–54; 1 Thessalonians 4:16.
God's mysterious plan for the world is not a surprise. The prophets who served God in the past warned that the day of the Lord would come (see Joel 2:1–3, 10–11; Amos 5:18–20; Zephaniah 1:14–18).