What will be the third plague?

Answer

"And the third angel poured out his vial upon the rivers and fountains of waters; and they became blood."
Verse 4.
NOTE-The second plague affects the sea. The third plague comes closer to the habitations of men,
and affects the land. The water supplies are contaminated.

How may one know that this does not refer to the earthly sanctuary ?
Why did God make His promise to the seed of Abraham?
Were the Ten Commandments a distinct and complete law by themselves?
Of what does God say the keeping or hallowing of the Sabbath is a sign?
24. What psalms seem to have been written especially for the comfort and encouragement of God's people during the time of the seven last plagues?
Out of what will they be judged?
14. What scripture for ever precludes the idea that the dead come back to earth to communicate with the living?

Questions & Answers are from the book Bible Readings for the Home Circle