KHIRBET QEIYAFA, Israel — Overlooking the verdant Valley of Elah, where the Bible says David toppled Goliath, archaeologists are unearthing a 3,000-year-old fortified city that could reshape views of the period when David ruled over the Israelites. Five lines on pottery uncovered here appear to be the oldest Hebrew text ever found and are likely to have a major impact on knowledge about the history of literacy and alphabet development.