Russell's take on the whole Viking massacre thing is that King Daddy deserved to be ripped apart by drug-addicted werewolves, for some reason, and that they were just there looking for goats to snack on. Also, Eric's dad was apparently a "self-important greedy little putz," et cetera. Russell is delivering this information to Eric, you remember, while they are lying in the sun like Sookie and Tara, sans SPF, smoking, skin flaking off.
Maybe because he is dying, maybe because he is crazy, but for whatever reason, Eric sees Godric looking down at him with a sort of distinctly Roma Downey glow about him. I haven't the time nor really the inclination to unpack this. There's a plot reason that this is interesting, because what Godric is saying to Eric has an effect on him, but it's for opposite reasons. And I don't know how the grief for Godric and the grief for the Vikings is connected.
And I don't know but that we all have better angels that show us the opposite of ourselves. Or that Godric went to heaven, because God's not as dumb as his people. It's weird and seems complicated, in a way that things about this show rarely are, so I'm going to say it's the usual ambiguity, as to whether Godric is real or not, but that he is also a voice of Eric's better nature.
It is my belief that everybody, down in the infinite chaos of the stuff you're not looking at, has tried every possible recipe, combining everything with everything else in fractal iteration, before arriving at the future perfect self, and that we're mostly just getting pulled along by that person. That the things that happen to you aren't scars or determinism but just the obstacles between you and that best possible person. Who maybe sometimes looks like Godric, if you're Eric, because that's how much you loved him. Who probably hands you just a little bit more than you thought you could handle, so that you grow a little more all the time.
So Godric wants Eric to forgive the King, to end the hate, before they die. They're just laying there, dying at pretty much the same rate -- even though Russell is as old or older than Godric was, no? -- because "forgiveness is love," and "Love is all." Probably that sounds less ridiculous in Viking language, but given Eric's response -- a sort of gut-wrenched childish scream -- maybe not. And when Eric says, "I swore to my father," he's getting at the very heart of the vampire issue, because he's telling Godric, father and brother and everything else, that this doesn't come under his emotional jurisdiction.