This is one of the most extraordinary passages in the entire Targum. Targum Pseudo-Jonathan on (Genesis 14:13) takes a single Hebrew word — ha-palit, the fugitive who brought news to Abram — and identifies him by name. It is Og.
The same Og who will reappear centuries later as the giant king of Bashan whom Moses defeats at Edrei (Numbers 21:33, Deuteronomy 3:11). The Targumist tells you that this Og is a survivor of the Flood itself. He rode the top of the ark, clinging to it like a barnacle, sustained by food that Noah handed him through the window.
And the Aramaic is blunt about why he was spared: not being spared through high righteousness, but that the inhabitants of the world might see the power of the Lord. Og survives the Flood not as a reward. He survives as an exhibit. The Holy One wants the post-flood world to see, in one living giant, what the antediluvian titans looked like. Og is a walking archaeology.
Now Og shows up at Mamre on the eve of the Pascha — Passover — while Abram is making unleavened cakes. The Targum has just dropped the first Passover into the patriarchal era, centuries before the Exodus. And Og's motive, in this reading, is dark. He hopes Abram will go to war against the four kings, that Abram will be killed, and that Og can then take Sarah for himself.
The Targumist is telling you that even news-bearers have agendas. Og, the giant messenger, is already planning his own betrayal. And Abram, who hears only your nephew has been captured, will rise to rescue Lot without knowing the giant beside him hopes he dies trying.
The covenant survives because God sees further than the messenger.