1 Kings 18:42-45 is the OT source story: Elijah prays on Carmel, a cloud appears, and heavy rain falls, directly matching James's summary.

In Job 37:12, the same divine direction of clouds is described—showing God commands the natural elements Elijah's prayer affected.

Job 38:34 asks if you can command the clouds—highlighting that only God can, as Elijah's prayer demonstrated.

Psalm 147:8 describes God covering the heavens with clouds and preparing rain—the very act Elijah prayed for.

Jeremiah 5:24 says people should fear God who gives rain—the same source Elijah trusted for the rain he prayed for.

Exodus 9:33 records Moses praying to end a rain/hail plague, paralleling Elijah's prayer to start rain—both show prayer affecting weather.

Leviticus 26:4 promises rain and land yield as covenant blessing, which Elijah's prayer exemplifies as God answers in faithfulness.

1 Kings 8:36 shows Solomon praying for rain when Israel repents, similar to the repentance context implied in James's example of Elijah.

2 Chronicles 6:27 parallels 1 Kings 8:36, repeating the prayer for rain as a sign of forgiveness, aligning with Elijah's story.

Job 12:15 declares God's sovereignty to withhold and send waters, which is precisely what happens in Elijah's drought and rain.

Jeremiah 14:22 affirms that only the Lord gives rain, underscoring that Elijah's answered prayer demonstrates God's exclusive power over nature.

Acts 14:17 describes God's general provision of rain and harvests, echoing the same divine action seen in the specific answer to Elijah's prayer.