That’s the choices in my mind. Granted, he’s both, but when it comes to how you read the Greek of Matthew 26:50, which character trait is more prominent? Here’s the text of verses 49–50; the key phrase is in bold:
καὶ εὐθέως προσελθὼν τῷ Ἰησοῦ εἶπεν· χαῖρε, ῥαββί, καὶ κατεφίλησεν αὐτόν. 50 ὁ δὲ Ἰησοῦς εἶπεν αὐτῷ· ἑταῖρε, ἐφ᾿ ὃ πάρει. τότε προσελθόντες ἐπέβαλον τὰς χεῖρας ἐπὶ τὸν Ἰησοῦν καὶ ἐκράτησαν αὐτόν.
Judas approaches Jesus, he greets him, kisses him, and he says either (1) “Friend, do that for which you are here,” or (2) “Friend, why are you here?”
If you think of Jesus in this moment as resolute and determined to drink his cup of suffering, you might read it as “Do that for which you are here.” I, however, because of my default way of thinking of Jesus like to read it, “Friend, why are you here?” The language could go either way, and that is why the translations almost always offer both options. They print the “determined-Jesus” reading in the text and usually offer the “sympathetic-Jesus” reading in the footnotes.
I imagine Jesus in this moment broken at the sight of his close friend being caught up in the destructive pattern he is living out. I imagine the scene with the camera zoomed in on Jesus’s face. His eyes are heavy and tired and perhaps tearing up. Face to face, he looks into Judas’s eyes and with one last attempt to disciple him he speaks to Judas’s confusion, “Friend, why are you here?”
I’ve always read it this way. I’ve never done any extensive study of the phrase in contemporary literature. I just think the sympathetic reading makes the most sense. I think the Gospels portray Jesus as one who bears with and is a friend of sinners, one who meets them in their moments of weakness, and because of that my primary reading is the translations’ alternate reading. I read this line as one of the most emotion filled, tense, dramatic moments in Matthew. It’s beautiful and heartbreaking.