Luke 4:25

But in truth I tell you, there were many widows in Israel in Elijah's time, when the heaven was closed for three years and a half, and there was a great famine over all the land,

Romans 10:9

For if with your lips you acknowledge the fact that Jesus is Lord, and in your hearts you believe that God raised Him from the dead, you will be saved.

Romans 15:9

and for the heathen peoples to praise God for His mercy, as the Scripture says: "For this I will give thanks to you among the heathen, and will sing praises to your name."

Revelation 11:6

They have the power to shut up the sky, so that no rain will fall upon the earth as long as they prophesy, and they have power over the waters to turn them into blood, and to smite the earth with any plague as often as they please.

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
But in truth I tell you, there were many widows in Israel in Elijah's time, when the heaven was closed for three years and a half, and there was a great famine over all the land,
Revelation 11:6
They have the power to shut up the sky, so that no rain will fall upon the earth as long as they prophesy, and they have power over the waters to turn them into blood, and to smite the earth with any plague as often as they please.

If they pray

Romans 10:9
For if with your lips you acknowledge the fact that Jesus is Lord, and in your hearts you believe that God raised Him from the dead, you will be saved.
Romans 15:9
and for the heathen peoples to praise God for His mercy, as the Scripture says: "For this I will give thanks to you among the heathen, and will sing praises to your name."