Through the course of interaction with His people, God occasionally changed someone's name. It was generally done to establish a new identity that God wished them to embody.
Why did some people's name change in the Bible?
The practice wasn't limited to Jews. Royalty from Assyria to Judah to Ancient Egypt to China often took different, public, names when they took the throne. It is tradition for a new Pope to take the name of a former pope whom he wishes to emulate—ever since Mercurius was named pope and thought it bad form for a Catholic pope to have the name of a Roman god. English royalty occasionally go by their middle names.
Most of the changed names in the Bible were changed by God. Here is a partial list:
Abram – Abraham: high father – father of many. At the time, Abram wasn't father of anyone directly, although he was the patriarch and acting father of his clan. God changed his name as a sign of His promise that Abraham would be the father of many nations. (Genesis 17:5)
Sarai – Sarah: my princess – mother of nations. Despite Sarah's doubts, God intended her to be the mother of many nations as well. (Genesis 17:15)
Jacob – Israel: supplanter – he who has the power of God. Jacob rose to position by manipulating his brother into giving him his firstborn birthright and then tricking his father, Isaac, into giving him the firstborn blessing. God wanted to make it clear that it was He who gave Israel power and position, not his own conniving ways. (Genesis 32:28)
Simon – Peter: God has heard – rock. On his own Peter was not a rock. He ran hot and cold depending on the circumstances. With the Holy Spirit, however, Peter became the stabilizing influence for the new church. (John 1:42)
There were also a few characters who went through a name change that was not ordained specifically by God.
Naomi – Mara: beautiful – bitter (Ruth 1:20). After her husband and sons died, Naomi attempted to change her name to Mara, or bitterness, to reflect her hard circumstances. Neither history nor her daughter-in-law Ruth indulged her, and before long, God again blessed her with a family.
Saul – Paul: Some think that God changed Saul's name to Paul after his conversion, but this isn't true. "Paul" is Greek for the Jewish "Saul." Since Paul was a Roman citizen and witnessed to the Greek-speaking world, it was reasonable for him to take a more familiar form of his own name. (Acts 13:9)
Joseph – Zaphenath-Paneah: When the Hebrew Joseph came into the service of the Pharaoh, he was given a new Egyptian name. (Genesis 41:45)
Daniel – Belteshazzar: When Daniel was taken into captivity to Babylon, and then taken to the court of Nebuchadnezzar, he was given a Persian name to replace his Hebrew name. See also Hananiah/Shadrach, Mishael/Meshach, and Azariah/Abednego. (Daniel 1:7)
Hadassah – Esther: The Jewess girl Hadassah (Myrtle) was also given a new name, Esther (star), when she was taken to be in Xerxes court. Incidentally, the name of the king, Ahasuerus, is a Jewish name, given in honor for Xerxes's decision to save the Jews. (Esther 2:7)
Finally, there is a name change for all believers: God says, "To the one who conquers I will give some of the hidden manna, and I will give him a white stone, with a new name written on the stone that no one knows except the one who receives it" (Revelation 2:17). When we reach heaven, God will also change our names. Perhaps it will represent our own changed identity as we transition from sinful to holy.
Did the people in the Bible have last names?
What are the names of Jesus Christ? What titles are ascribed to Jesus in the Bible?
What are the names of God? What do the names of God mean?
What names and titles does the Bible use for the Holy Spirit?
Why should we read the Old Testament?
Truth about Everything Else