Acts 26:2

ἥγημαι ἐμαυτὸν μακάριον, I think myself happy. Because Agrippa was sure to understand much of the feeling imported into the case which would be entirely obscure to a Roman magistrate. Paul would thus be able to make his position clear, and get it explained through Agrippa to the Roman authorities.

ἐπὶ σοῦ, before thee. So Acts 24:19, and frequently in N.T. ἐπί with genitive in this sense is also found in classical Greek, but not so commonly with a personal pronoun. For an example of the use, cf. Acta Pauli et Theclæ, 16, εἰπάτω ἐπὶ σοῦ τίνος ἔνεκεν ταῦτα διδάσκει.