On the YouTube channel “Χριστιανισμός”, which Modern Greek Bible version do they read from? Gallipoli? Seraphim?

OP, you know about the first translation of the New Testament into Modern Greek by Maximus of Gallipoli, in 1638! That is awesome!

And it would be awesome if that was the version that the channel used in the video:

But no. The text is Neophytos Vamvas’ translation, and you can read along here:

N. Vamvas (Bambas) Old and New Testament

You did some great detective work: of course it’s Byzantine Text Type, it’s an Orthodox translation.

The language does look a bit old fashioned, doesn’t it? Not just Koine old fashioned, and not straying very far from the syntax of the original: Τας εντολάς εξεύρεις “you know the commandments”. It sounds not just katharevousa, but positively 18th century.

And indeed: his New Testament translation dates from 1833, with the Old Testament following in 1850.

Here’s the Wikipedia article about the translation: Η Αγία Γραφή, Τα Ιερά Κείμενα Μεταφρασθέντα εκ των Θείων Αρχετύπων – Βικιπαίδεια. And here’s a speech about him from the Archbishop of Athens: Ο Αρχιεπίσκοπος κ. Ιερώνυμος μιλά για τον Νεόφυτο Βάμβα.

The Church of Greece seems to be friendlier towards him now than it would have been at the time: he (or his collaborators) translated the Old Testament from the Hebrew and not from the Septuagint, and knowing he’d get no support from the Orthodox Church, he’d cooperated with the protestant British and Foreign Bible Society, which the Orthodox Church loathed. (In fact his translation is the preferred translation of the Evangelical and Pentecostal churches of Greece, and had also initially been the translation used by the Jehovah’s Witnesses.) This Orthodox blog post attacks it as a translation from the King James Bible: Λάθη στή μετάφραση τοῦ Βάμβα. Χρήστος Σαλταούρας.

Vamvas got the idea for the translation in Paris, working with Adamantios Korais, started the translation as a teacher in Corfu, completed it as a teacher in Syros, and then got a job as a philosophy lecturer in the new University of Athens, where he ended up as Dean of Arts.

The Vamvas translation was the only modern translation until the 1960s that didn’t provoke street riots (unlike the demotic translation of the New Testament by Pallis in 1902); and given that it is not a Demotic translation, I suspect it is the favourite of the Orthodox church now, even if they distanced themselves from it beforehand.