Albert Barnes Commentary 2 Chronicles 20:6-9

"and he said, O Jehovah, the God of our fathers, art not thou God in heaven? and art not thou ruler over all the kingdoms of the nations? and in thy hand is power and might, so that none is able to withstand thee. Didst not thou, O our God, drive out the inhabitants of this land before thy people Israel, and give it to the seed of Abraham thy friend for ever? And they dwelt therein, and have built thee a sanctuary therein for thy name, saying, If evil come upon us, the sword, judgment, or pestilence, or famine, we will stand before this house, and before thee, (for thy name is in this house,) and cry unto thee in our affliction, and thou wilt hear and save." — 2 Chronicles 20:6-9 (ASV)

Jehoshaphat’s appeal is threefold:

1. To God omnipotent (2 Chronicles 20:6).
2. To “our God.”
3. To the God especially “of this house,” the temple.

2 Chronicles 20:7

Abraham your friend. Historically, this is the first use of this remarkable expression, which was repeated later. The basis for this expression is found primarily in Genesis 18:23-33, where Abraham spoke with God as a man speaks with his friend .

2 Chronicles 20:8–9

The appeal recalls Solomon’s prayer, which God had formally accepted by sending down fire from heaven to consume the accompanying offering.