In the Rime of the ancient Mariner, what is the moral of the poem?Thisold guy comes to the wedding, the "guest" listens to his tales and thenis...

Yes, all kimfuji says I agree with, but we need to back up a bit. The Ancient Mariner's enlightenment begins when he carelessly kills the albatross:

At length did cross an Albatross,
Thorough the fog it came;
As it had been a Christian soul,
We hailed it in God's name.
It ate the food it ne'er had eat,
And round and round it flew.
The ice did split with a thunder-fit;
The helmsman steered us through!
And a good south wind sprung up behind;
The Albatross did follow,
And every day, for food or play,
Came to the mariner's hollo!
In mist or cloud, on mast or shroud,
It perched for vespers nine;
Whiles all the night, through fog-smoke   white,
Glimmered the white moonshine."
God save thee, ancient Mariner,
From the fiends that plague thee thus! -
Why look'st thou so?' -"With my crossbow
I shot the Albatross."

It was after that when everything began to fall into ruin and death for all but the lone Mariner. Eventually, after suffering and inner struggle, he saw the truth: that all life is to be respected, no matter how gross or slimy or seemingly foul. You don't just go kill a creature of God's making because you have nothing better to do. I don't know about the rest of you, but I even have trouble killing bees and mosquitos. And part of my reluctance to do so comes from what I learned from this poem when I first read it back in tenth grade. Thank you Mr. Beale, wherever you are!
Remember now: the Ancient Mariner stops a wedding guest who is about to go into a wedding. The Mariner holds the guest with his skinny hand and a story that has to be told. And in a way, the story is about a marriage, a wedding of sorts... wherein a man comes to realize that he is one with all life on earth.