Genesis 17:1 When Abram was ninety-nine years old, the LORD appeared to him and said, “I am God Almighty; walk before me faithfully and be blameless. 2 Then I will make my covenant between me and you and will greatly increase your numbers.”
3 Abram fell facedown, and God said to him, 4 “As for me, this is my covenant with you: You will be the father of many nations. 5 No longer will you be called Abram; your name will be Abraham, for I have made you a father of many nations. 6 I will make you very fruitful; I will make nations of you, and kings will come from you.
In the beginning we see God gave Adam the job of naming the animals. By giving something its name, you not only give it an identity (how you and others will know it) but you also claim a sort of stewardship over it. Think of parents naming a child, a family naming their new dog-this sense of stewardship was even greater 2000 years ago. Names in Jewish culture had great significance. It is common in scripture for God to give people new names, after interacting with them. We see this with Abram in Genesis 17, Jacob in Genesis 22 and many other times. A really interesting example of the power and meaning of names is in the book of Daniel.
Daniel 1:6 Among those who were chosen were some from Judah: Daniel, Hananiah, Mishael and Azariah. 7 The chief official gave them new names: to Daniel, the name Belteshazzar; to Hananiah, Shadrach; to Mishael, Meshach; and to Azariah, Abednego.
Their original hebrew names reffered to the God of Israel, but the Babylonian king had them named to relate them to the Babylonian gods. Turning Hananiah "God who is gracious" to Shadrach "command of the moon god." Mishael "Who is like God" to Meshach "Who is what Aku [name of a god] is?" and Azariah "God has helped" to Abednego "servant of the god Nebo."
What someone calls you, and how someone refers to you is important. I believe as God renamed Abram, renamed Jacob-He has also renamed us. Notice Abraham and Jacob did not leave their interactions with God unchanged, neither should we. When we meet with God we are changed, sometimes we are even given something to mark that interaction,like Jacob's limp, or we may simply choose baptism as this sign. The beautiful thing though, is that in Christ we have new identities, and just like for these men thousands of years ago- that change has power.