The names Land of Israel and Children of Israel have historically been used to refer to the biblical Kingdom of Israel and the entire Jewish people respectively. The name "Israel" (Standard Yisraʾel, Isrāʾīl; Septuagint Greek: Ἰσραήλ Israēl; 'El(God) persists/rules' though, after Hosea 12:4 often interpreted as "struggle with God") in these phrases refers to the patriarch Jacob who, according to the Hebrew Bible, was given the name after he successfully wrestled with the angel of the Lord. Jacob's twelve sons became the ancestors of the Israelites, also known as the Twelve Tribes of Israel or Children of Israel. Jacob and his sons had lived in Canaan but were forced by famine to go into Egypt for four generations, lasting 430 years, until Moses, a great-great grandson of Jacob, led the Israelites back into Canaan during the "Exodus". The earliest known archaeological artifact to mention the word "Israel" is the Merneptah Stele of ancient Egypt (dated to the late 13th century BCE).
Who was Moses?
a great-great grandson of Jacob