John Wesley on Revelation 16:1

Pour out the seven phials - The epistles to the seven churches are divided into three and four: the seven seals, and so the trumpets and phials, into four and three. The trumpets gradually, and in a long tract of time, overthrow the kingdom of the world: the phials destroy chiefly the beast and his followers, with a swift and impetuous force. The four first affect the earth, the sea, the rivers, the sun; the rest fall elsewhere, and are much more terrible.