When gods are contrary They stand by no one. (2.532-533)
Another way of stating this sentiment would be, "When it rains, it pours." Like all of classical literature, the Aeneid presents a highly nuanced view of the gods. Even though they're sometimes on your side (especially if you honor them with sacrifices and prayers), if they turn against you, it can be deadly. The destruction of Troy – the context of these lines – definitely falls into the second category.
(Helenus): 'Another thing: when you have crossed and moored Your ships ashore, there to put up your altars For offerings, veil your head in a red robe Against intrusions on your holy fires, Omen-unsettling sights amid your prayers. You and your company retain this ritual Veiling in the future, let your progeny Hold to religious purity thereby.' (3.545-552)
When performing a sacrifice, it was very important to make sure you got all the details of the ritual right – otherwise you might mess up the whole thing. As a rule of thumb, whenever you hear a character in the Aeneid talk about how a tradition that happens "now" (i.e., in the world of the Aeneid) will continue to happen in the "future," there's a good chance that it might refer to something in the present in which Virgil is writing. In this case, Helenus is probably referring to the return of old-time religion that Augustus brought about, in order to distract people from his radical political reforms. Heck, in this statue the guy even had himself depicted veiling his head while making a sacrifice – just like Helenus says.
So he called out, then turned to poke the embers, The drowsing fire on his hearth, and paid His humble duty to the Lar of Troy And Vesta's shrine—the goddess of the hearth— With ground meal, as in ritual sacrifice, And a full incense casket. (5.968-973)
These lines could just as well go under the theme of Duty – and that's just the point! Most religions impose various obligations on the believer, and that of the ancient Romans was no exception. Can you think of other moments in the Aeneid when these two ideas are intertwined?
(Aeneas): "Poor fellow, how Could rashness take you this way? Don't you feel A force now more than mortal is against you And heaven's will has changed? We'll bow to that!" (5.602-605)
Were we suggesting that Augustus might have been using religion as a pretext? We were. But hey, it isn't only real people who can do it – quasi-fictional characters like Aeneas can, too! In this case, Aeneas is invoking the gods to break up the boxing match between Entellus and Dares, saying that Entellus clearly has a divinity helping him. The only problem is, Virgil hasn't told us about any gods getting involved, so it's a safe bet Aeneas didn't see one either. So long as the gods often act invisibly, the chances are high that someone will claim they've been acting one way or the other when the moment calls for it.
(Palinurus): "Phoebus's caldron Told you no lie, my captain, and no god Drowned me at sea. The helm that I hung on to, Duty bound to keep our ship on course, By some great shock chanced to be torn away, And I went with it overboard." (6.470-475)
Palinurus's words here show us that even the dead can't be trusted to give an honest account of what killed them. (Well, at least the dead who are waiting on the banks of the River Styx to be ferried across.) That's because we know, from the end of Book 5, that Palinurus was actually knocked overboard by Somnus, the god of sleep (who approached Palinurus disguised as Phorbas, another Trojan). Because the gods sometimes acted invisibly, practically anything could be interpreted as an instance of divine meddling. Check out the third quotation for this theme to see an example of how a skillful politician could exploit this uncertainty when the moment called for it.
(The Sibyl): "A further thing is this: your friend's dead body— Ah, but you don't know!—lies out there unburied, Polluting all your fleet with death While you are lingering, waiting on my counsel Here at my door. First give the man his rest, Entomb him; lead black beasts to sacrifice; Begin with these amends." (6.217-223)
Another common feature of many religions is that of obligation to the dead. In ancient Greek and Roman religion, an unburied dead body could be said to "pollute" the living. We put "pollute" in quotation marks because it isn't simply a question of stinking up the place, though that did probably happen (sorry, but it's true). More than that, though, the "pollution" could take on an almost magical character, which could only be washed away by performing certain rituals – like the sacrifice of black beasts the Sibyl recommends.
That day By chance, as he blew notes on a hollow shell, Making the sea sing back, in his wild folly He dared the gods to rival him. Then Triton, Envious, if this can be believed, Caught him and put him under in the surf Amid the rocks off shore. (6.245-251)
A word of advice from Shmoop to you: if you're ever magically transported back in time to the mythical past, please don't tell the gods you're better than them at something. (Not even if it's something that hadn't been invented yet – like video-games or…pogo-sticking, or whatever. It's just not worth risking it.) How does this little episode echo or contrast with other scenes in the Aeneid that deal with conflict between gods and mortals?
Bearing these gifts and offers from Latinus, Aeneas' legates, mounted now, returned, And they brought peace. Only look upward, though, At Jove's unpitying queen. (7.385-389)
This quick transition between everything looking OK to everything being very not OK is another example of the theme of how the gods can mess things up for you.
(Tiberinus): "Son of Venus, rise. Now, while the early stars of evening set, Address your prayers in proper form to Juno, Melt with your pleas her menaces and anger." (8.78-81)
Generally speaking, Tiberinus is giving Aeneas good advice. That is to say, if there's anything you can do to bring the gods on your side, sacrifices and prayers are a good place to start. So how about that moment when Juno listens to Aeneas's prayers and stops hating him? Sorry. There's no such moment. She just finally gives up in Book 12; Aeneas had nothing to do with it. Really, these lines just provide more proof that the gods can really make life hard for you.
When Dawn came up from Ocean in the east, Though Pallas' death had left Aeneas shaken, And duty pressed him to give time For burial of the dead, he first In early light discharged his ritual vows As victor to the gods. (11.1-6)
This quotation, like the fourth quotation for this theme, shows the close connection between religion and the idea of Duty. This quotation could have just as easily gone under that theme.