No: the words of a Gospel writer, with an agenda. It simply does not make any kind of sense to accept the main message of Jesus - one of love and forgiveness - with the idea of a vengeful Being. The two concepts are irreconcilable.
You're absolutely right, it doesn't. From a religious point of view, as a Christian, you accept that the words of Jesus are correct, the depiction of a caring, kind, all-loving incarnation of God. That's fine.
As a scholar, presumably, you have to approach the text from a neutral point of view, surely. You have to have a reason - not a preconception or a desire - to think that the depiction of Jesus is a more accurate reflection than the depiction of the Old Testament deity.
What scholarly method do you use to determine 'this section is true' or 'this section has been corrupted/twisted/repurposed', without resorting to 'Jesus has to be kind, so therefore...'
O.