Samuel was a prophet and the last of the judges of Israel, who anointed Saul as Israel's first king and later anointed David; his story opens in 1 Samuel.
1 Samuel 1:20 in the King James Version reads:
Wherefore it came to pass, when the time was come about after Hannah had conceived, that she bare a son, and called his name Samuel, saying, Because I have asked him of the LORD.
The verse appears in 1 Samuel 1, in the account of Samuel's birth to Hannah. Read it in context at 1 Samuel 1:20, or the full chapter at 1 Samuel 1. Encyclopedia entry: en.wikipedia.org/wiki/Samuel.