Is God obligated to keep the promises He made in the Bible?
Yes. When God has said something, He becomes duty bound to fulfill His Word; otherwise the Bible would be a lie. He is duty bound and will fulfill what He said He would do. This is because He has spoken it, and His Word must stand.
Les teaches that although Paul wrote it, God said it, and this is where He wants us to come. When we say, "God, You've said it, I believe it with all my heart," God becomes duty bound. He is duty bound to fulfill His Word; otherwise this Book is a lie. But He is duty bound, and He will fulfill what He said He would do. This connects to believing with the heart unto righteousness, not mere head knowledge.