Blessing the World With A Blessed People:
God called a man name Abraham to set the world right. God set apart Abraham and his descendants (Israel) to live devoted to God, obey His voice, and receive His blessing. The purpose of this specially blessed people was to bless everyone in the world. The descendants of Abraham were to eventually become a nation devoted to God, a bright light in a dark world designed to show all people what life is supposed to look like, and so draw all people into God's blessing.
These beautiful and broken people, set apart to set the world right, were at times a part of the solution, but were often a part of the problem. Israel disobeyed God in all sorts of ways: oppressing the poor, doing injustice to the innocent, worshipping other gods, murder, adultery, prostitution, and even child sacrifice. The special people given God's blessing, laws, and presence to bring all people into relationship with God were just as sinful and guilty as everyone else, compounding on the ruin of Creation. God neither gave up on His people nor the world He created.