David moved his parents to Moab in order to protect them from Saul. Being well advanced in years, they would not have been able to endure the life of a fugitive.1 If they were outside of Saul’s territory, then Saul would not be able to harm them directly. With Ruth being David’s great-grandmother, there would have been some natural family connections with the people of Moab. Quite possibly David made use of these connections in his request to the king of Moab,2 and the king granted his request because he was an enemy of Saul and supportive of a split that would weaken Saul.3 David would later fight against Moab and defeat them in battle (2 Samuel 8:2).
3 De là David s'en alla à Mitspé dans le pays de Moab. Il dit au roi de Moab: Permets, je te prie, à mon père et à ma mère de se retirer chez vous, jusqu'à ce que je sache ce que Dieu fera de moi.