Luke 4:25

And I assure you, there were many widows in Israel, in the days of Elias, when the heaven was shut up for three years and six months, and there was a great famine through all the land;

Romans 10:9

and believe in thine heart, that God hath raised Him from the dead, thou shalt be saved.

Romans 15:9

and that the Gentiles might glorify God for his mercy, as it is written, "For this cause will I celebrate Thee among the Gentiles, and sing praises unto thy name."

Revelation 11:6

These have power to shut the heavens, so that no rain may fall in the days of their prophecy: and they have power over the waters to turn them into blood, and to smite the earth with every plague as often as they will.

Treasury of Scripture Knowledge

Summary

When heaven is shut up, and there is no rain, because they have sinned against thee; if they pray toward this place, and confess thy name, and turn from their sin, when thou afflictest them:

If they pray

Bible References

Heaven

Luke 4:25
And I assure you, there were many widows in Israel, in the days of Elias, when the heaven was shut up for three years and six months, and there was a great famine through all the land;
Revelation 11:6
These have power to shut the heavens, so that no rain may fall in the days of their prophecy: and they have power over the waters to turn them into blood, and to smite the earth with every plague as often as they will.

If they pray

Romans 10:9
and believe in thine heart, that God hath raised Him from the dead, thou shalt be saved.
Romans 15:9
and that the Gentiles might glorify God for his mercy, as it is written, "For this cause will I celebrate Thee among the Gentiles, and sing praises unto thy name."