The reflexive pronoun "himself" emphasizes that it is the Father, not someone less important, who has testified. (See: [[rc://en/ta/man/translate/figs-rpronouns]])
This is an important title for God. (See: [[rc://en/ta/man/translate/guidelines-sonofgodprinciples]])
# the very works that I do, testify about me
Here Jesus says that the miracles "testify" or "tell the people" about him. AT: "What I do shows the people that God has sent me" (See: [[rc://en/ta/man/translate/figs-personification]])
# You do not have his word ... in you, for you are not believing in the one whom he has sent
"Word" here is a metonym for "message." AT: "You do not believe in the one he has sent. That is how I know that you do not have his message remaining in you" (See: [[rc://en/ta/man/translate/figs-metonymy]])