“Now when Jesus heard
That John had been arrested,
Ἀκούσας δὲ ὅτι Ἰωάνης παρεδόθη ἀνεχώρησεν εἰς τὴν Γαλιλαίαν.
This is the same as Mark, chapter 1:14 and similar to Luke, chapter 4:14. Jesus heard (Ἀκούσας δὲ) that John the Baptist had been arrested (Ἰωάνης παρεδόθη), without any clear indication why. However, in chapter 14:1-12, Matthew took up this question in greater detail. Herod Antipas, the son of King Herod, was in charge of Galilee from 4 BCE-39 CE. Although this text does not mention him by name, Herod Antipas was the one who arrested John. This might have been a warning sign to get away from the Jordan River area. However, Jesus went back to Galilee, just like Joseph had done years earlier. Galilee was about 80 miles north of Jerusalem and the Dead Sea area.