Why did isriallites believe david was there greatest

As king, David was a warrior who protected the land of God's people, and Jehovah saved David wherever he went. During his reign, the nations boundaries were extended from the river of egypt to the river euphrates. David's reputation lived on well after his death, even today. 

This is because he fought golaiath and he was brave and trusted God and was a very good role model to them

Americans often speak of their country as one of several large regions.  these regions are cultural units rather than governmental units --  formed by history and geography and shaped by the economics, literature and folkways that all the parts of a region share. what makes one region different from another? a region's multicultural heritage as well as distinct demographic characteristics like age and occupation make regions different and special. within several regions, language is used differently and there are strong dialects. there are also differences in outlook and attitude based on geography.