I read the poem's moral as one of redemption through love and prayer. The Mariner relates his moral, but in class we raised a few questions about the characters of the final scene. Why is the wedding guest wiser and sadder, why is the Mariner wrought with occasional agony? How does this exemplify a moral?
My reading arrives at an answer to these questions, but I want to jump back to the "sin." The Mariner kills the bird. We don't know "why," just that it was wrong (which we learn after we get the crew's swaying, unstable view of the nature of the action). The Mariner must be judged for his actions. We see this in the crew, but then a higher force comes into play to solidify the notion of a need for judgment against the Mariner. The fate of the Mariner is left to a gamble and of course, life-in-death wins out. I find this interesting in a Biblical context considering Biblical views on finding life through death, both in salvation through Christ's resurrection and also through the instructions to "die" to the "world" in order to find a true life apart from it.
A higher force judges and the Mariner is left to face the judgment. For some time he wallows in this judgment. A change occurs however after being surrounded so long by death, when the Mariner finds joy in life. He now sees the previously ugly sea-creatures as beautiful because of the life they have. So moved (through seeing these creatures of nature) is the Mariner that he is filled with love for them. Only through his love is he able to pray, which is the beginning of his redemption. From there, higher forces are at work to redeem him from "death," evidenced in the fall of the Albatross from around his neck. The cause and effect discussed (in class) has made me arrive at this reading.
Once the Mariner is back, he runs into the three people. I found this scene interesting as it again stresses the importance of love for all creation. The pilot and his son judge (as did the crew) the Mariner, labeling him as a demon, either through fear perhaps, or through an unloving nature possibly. What I find is important, however, is that the loving--or should I say non-judging--Hermit is the only one not negatively affected by the meeting. His good (loving) nature and lack of judgment seems to play out for the better compared to the pilot and his son.
This sort of rounds us back to the Mariner and the Guest.
The Mariner has an agony which I read as both his penance, but also as a love. He knows the people (when seeing their face) whom he must speak to. He relates his tale because he is in anguish to do so, but could anguish stem from love? I see the Mariner so full of love that he must tell his tale of redemption in an effort of love for all life. He sees pain in the guest and is led through love to tell him his tale of redemption.
The guest in the end, however, has been told the moral--love and pray. The guest is wiser from the lesson, but sadder perhaps because he has not reached the point of love, though he now knows its importance. The same might be said of prayer. The guest knows the moral, but is not ready to live accordingly.
I know I'm arriving at the moral through my reading, but is not that generally the case?