Joshua 7 reminds us that God's people do not live by momentum. Yesterday's victory cannot substitute for today's obedience. The God who fought for Israel at Jericho is the same God who allowed Israel to fail at Ai—not because He had changed, but because His people had.

David had sinned, and he knew it. He had taken another man’s wife, arranged a murder to cover it, and then carried on as if nothing had happened. Perhaps in the busyness of his royal life, he thought it was hidden away—buried in the past, forgotten even by himself. But God had seen it, and God sent Nathan.