Who is the summoner mentioned in the noble verse: "That Day, they will follow the summoner, from whom there is no deviation"?

Allah Almighty was asked about the state of the mountains on the Day of Resurrection, and He answered that they will be leveled and pulverized to the ground, becoming a flat plain with no crookedness. On that Day, people will follow the caller to the Standing without deviation, and voices will be humbled before the Most Merciful, so nothing will be heard but a whisper. The caller is Israfil (peace be upon him), who will call the people to the Standing of Resurrection.