Genesis 18 is about a man who was a friend of God. Because God had a relationship with Abraham He wanted to let him in on what He was about to do, destroy Sodom and the cities of the plain. The text says that they walked and talked together and that God revealed His mind and heart to Abraham. Abraham was concerned about Sodom because his nephew Lot lived there. He began to engage God in what seems like bartering for souls. It really is intercession. God has a burden on His heart. He lays that burden on His friend the intercessor and the intercessor goes back and forth with God till he dispatches the burden. When he or she is convinced God has heard he stops praying. She then waits and watches. What burden has the Lord laid on you to intercede for?