Jesus goes down to Galilee and heals a boy. Verse 44 gives us background information about something Jesus had said previously. (See: rc://en/ta/man/translate/writing-background)
For Jesus himself declared
The reflexive pronoun "himself" is added to emphasize that Jesus had "declared" or said this.. You can translate this in your language in a way that will give emphasis to a person. (See: rc://en/ta/man/translate/figs-rpronouns)
a prophet has no honor in his own country
"people do not show respect or honor to a prophet of their own country" or "a prophet is not respected by the people in his own community"
at the festival
Here the festival is the Passover.