From John Chapter 1:
John was standing with two of his disciples, and as he watched Jesus walk by, he said, “Behold, the Lamb of God.”
The two disciples heard what he said and followed Jesus.
Jesus turned and saw them following him and said to them, “What are you looking for?”
They said to him, “Rabbi” — which translated means Teacher —, “where are you staying?”
He said to them, “Come, and you will see.”
So they went and saw where Jesus was staying, and they stayed with him that day.
It was about four in the afternoon.
Andrew, the brother of Simon Peter, was one of the two who heard John and followed Jesus. He first found his own brother Simon and told him, “We have found the Messiah” — which is translated Christ —.
Then he brought him to Jesus.
Jesus looked at him and said, “You are Simon the son of John; you will be called Cephas” — which is translated Peter.
The first reading at Mass today is the (somewhat comical) passage from Samuel in which the Lord repeatedly calls to the prophet in his sleep and Samuel replies, "Here I am." In honor of that passage, here are two versions of the hymn "Here I am, Lord" by Dan Schutte: