Israel is important to God because he made a promise about it to a man called Abraham: God promises that he would give that area of the world to Abraham and his descendants, the Jews (the Children of Israel).
{18} “To your offspring I give this land, from the river of Egypt to the great river, the river Euphrates, {19} the land of the Kenites, the Kenizzites, the Kadmonites, {20} the Hittites, the Perizzites, the Rephaim, {21} the Amorites, the Canaanites, the Girgashites and the Jebusites.” (Gen. 15:18-21)
{13} Remember Abraham, Isaac, and Israel, your servants, to whom you swore by your own self, and said to them, ‘I will multiply your offspring as the stars of heaven, and all this land that I have promised I will give to your offspring, and they shall inherit it forever.'” (Ex. 32:13)