“behold.” The Greek word is idou (#2400 ἰδού), and it is used to get our attention. See commentary on Matthew 1:20 (“Look!).
“a leader came and bowed down before him.” The “leader” is named Jairus, and he was one of the leaders of the synagogue in Capernaum. The record of the healing of Jairus’ daughter and the healing of the woman who was bleeding is in Matthew 9:18-26; Mark 5:22-43; and Luke 8:41-56. Jairus had a great need, and showed respect to Jesus in asking for his help. For more on this event occurring in Capernaum, see commentary on Luke 8:40.
“bowed down before.” The synagogue leader did not think Jesus was God and likely did not even believe he was the Messiah, but rather was paying him homage, as he would to a superior, or to a prophet of God. See commentary on Matthew 2:2.
“My daughter has just died.” This is a summary statement of the sum of the events of this record, which occurs in Matthew, Mark, and Luke. Technically, Jairus came to Jesus and the daughter was still alive but near death, but died while Jairus was with Jesus, at which point Jairus let Jesus know that, but Matthew did not include all the details and the chronology of the event. Matthew’s Gospel is a summary of events.
“come and lay your hand on her, and she will live.” This is remarkable because Jesus had not yet raised anyone from the dead.