Why did God change Jacob's name to Israel? I am reading the book of Genesis, and I have noticed that God changes certain people's names, such as Abram to Abraham and Jacob to Israel. Why does he change their names? What does it symbolize?


  Now that Jacob had returned from Paddan-aram, God appeared to him again at Bethel. God blessed him, saying, "Your name is Jacob, but you will not be called Jacob any longer. From now on your name will be Israel." So God renamed him Israel. (Genesis 35:9-10, NLT )
Names were considered to be meaningful in some way.  For example, the younger of Isaac's twin sons with Rebekah was named Jacob ("supplanter") because when he was born he was holding on to Esau's heel, as if attempting to overtake him.  (Genesis 25: 24-26)

After Jacob's wrestle with the angel, when he demanded a blessing from the Lord, the angel pronounced a blessing upon him, and a new name to go with it: Isra-El, which can mean "He who prevails with God," or "May God prevail," depending on the context.

Likewise with Abram ("Exalted father"), when he was blessed by the Lord in Genesis 17, he was given the name Abraham ("Father of a multitude"), in keeping with the promise of the Lord:


  5 Neither shall thy name any more be called Abram, but thy name shall
  be Abraham; for a father of many nations have I made thee.
  
  6 And I will make thee exceeding fruitful, and I will make nations of
  thee, and kings shall come out of thee.


So we see that these different names are given to people as a blessing from the Lord, to signify that something about them, their nature or their life, has changed in some way.