"I looked up and saw the very last thing I expected: a huge lion coming slowly towards me. And one queer thing was that there was no moon last night, but there was moonlight where the lion was. So it came nearer and nearer. I was terribly afraid of it. You may think that, being a dragon, I could have knocked any lion out easily enough. But it wasn't that kind of fear. I wasn't afraid of it eating me, I was just afraid of it – if you can understand." (7.34)
Eustace's fear of Aslan isn't a fear of any particular thing: Aslan simply inspires fear, in a good way. It's a deep awe that comes from recognizing something far more powerful than yourself and knowing that you have to submit to that power.
Across the grey hillside above them – grey, for the heather was not yet in bloom – without noise, and without looking at them, and shining as if he were in bright sunlight though the sun had in fact gone in, passed with slow pace the hugest Lion that human eyes have ever seen. In describing the scene Lucy said afterwards, "He was the size of an elephant," though at another time she only said, "The size of a cart-horse." But it was not the size that mattered. Nobody dared to ask what it was. They knew it was Aslan. (8.82)
Lucy can't really explain how big Aslan was when he made this appearance, because his exact size doesn't really matter. He's just giving an impression of size and strength and seems bigger than normal. How much bigger isn't clear, and doesn't need to be.
But when she looked back at the opening words of the spell, there in the middle of the writing, where she felt quite sure there had been no picture before, she found the great face of a lion, of the Lion, Aslan himself, staring into hers. It was painted such a bright gold that it seemed to be coming towards her out of the page; and indeed she never was quite sure afterwards that it hadn't really moved a little. At any rate she knew the expression on his face quite well. He was growling and you could see most of his teeth. She became horribly afraid and turned over the page at once. (10.22)
Lucy is afraid of Aslan at this moment, not because Aslan himself is terrible but because she knows she has been wishing for a terrible thing that would bring on Aslan's anger.
Lucy looked along the beam and presently saw something in it. At first it looked like a cross, then it looked like an aeroplane, then it looked like a kite, and at last with a whirring of wings it was right overhead and was an albatross. It circled three times round the mast and then perched for an instant on the crest of the gilded dragon at the prow. It called out in a strong sweet voice what seemed to be words though no one understood them. After that it spread its wings, rose, and began to fly slowly ahead, bearing a little to starboard. Drinian steered after it not doubting that it offered good guidance. But no one except Lucy knew that as it circled the mast it had whispered to her, "Courage, dear heart," and the voice, she felt sure, as Aslan's, and with the voice a delicious smell breathed in her face. (12.59)
It's interesting that when they are visited by Aslan in the form of the albatross, none of the crew of the Dawn Treader even think to question it. They all instinctively know that the bird is good and is offering them a way out of a difficult situation.
And every night they saw that there rose in the east new constellations which no one had ever seen in Narnia and perhaps, as Lucy thought with a mixture of joy and fear, no living eye had seen at all. (13.1)
The "mixture of joy and fear" that Lucy feels here is similar to the feeling that the narrator suggests is inspired by the presence of something divine.
Now they could see that it was a tall girl, dressed in a single long garment of clear blue which left her arms bare. She was bareheaded and her yellow hair hung down her back. And when they looked at her they thought they had never before known what beauty meant. (13.51)
Ramandu's daughter is impressive and striking. In fact, she's so striking that Edmund implies she is similar in some ways to the White Witch. In this case, however, the powerful woman is actually on the side of good and right – a rare event in the Narnia chronicles!
Once or twice before, the Narnians had wondered whether the sun at its rising did not look bigger in these seas than it had looked at home. This time they were certain. There was no mistaking it. And the brightness of its ray on the dew and on the table was far beyond any morning brightness they had ever seen. And as Edmund said afterwards, "Though lots of things happened on that trip which sound more exciting, that moment was really the most exciting." For now they knew that they had truly come to the beginning of the end of the world. (14.3)
The truly exciting events in The Voyage of the Dawn Treader aren't the battles with sea serpents or the struggles against invisible enemies. The most striking thing that happens to Edmund and the others on this journey is realizing how close they are getting to something sacred and powerful at the end of the world.
Very soon after they had left Ramandu's country they began to feel that they had already sailed beyond the world. All was different. For one thing they all found that they were needing less sleep. One did not want to go to bed nor to eat much, nor even to talk except in low voices. Another thing was the light. There was too much of it. The sun when it came up each morning looked twice, if not three times, its usual size. And every morning (which gave Lucy the strangest feeling of all) the huge white birds, singing their song with human voices in a language no one knew, streamed overhead and vanished astern on their way to their breakfast at Aslan's Table. A little later they came flying back and vanished into the east. (15.1)
The last stage of the Dawn Treader's voyage to the east has a timeless, dreamlike quality. The travelers no longer need to divide their day into rest and wakefulness or observe set mealtimes.
And one by one everybody on board drank. And for a long time they were all silent. They felt almost too well and strong to bear it; and presently they began to notice another result. As I have said before, there had been too much light ever since they left the island of Ramandu – the sun too large (though not too hot), the sea too bright, the air too shining. Now, the light grew no less – if anything, it increased – but they could bear it. They could look straight up at the sun without blinking. They could see more light than they had ever seen before. And the deck and the sail and their own faces and bodies became brighter and brighter and every rope shone. (15.47)
Aslan knows what he's doing – just when it seems like the crew of the Dawn Treader is going to be overwhelmed by the glory of the sun at the end of the world, he provides them with magic water that helps them to bear its power.
Every day and every hour the light became more brilliant and still they could bear it. No one ate or slept and no one wanted to, but they drew buckets of dazzling water from the sea, stronger than wine and somehow wetter, more liquid, than ordinary water, and pledged one another silently in deep draughts of it. And one or two of the sailors who had been oldish men when the voyage began now grew younger every day. Everyone on board was filled with joy and excitement, but not an excitement that made one talk. The further they sailed the less they spoke, and then almost in a whisper. The stillness of that last sea laid hold on them. (16.3)
The kind of awe that Lucy and her friends feel as they approach Aslan's country isn't a loud, passionate, ecstatic joy. It's a solemn feeling that makes them want to be quiet and absorb everything that's happening around them.
Day after day from all those miles and leagues of flowers there rose a smell which Lucy found it very hard to describe; sweet – yes, but not at all sleepy or overpowering, a fresh, wild, lonely smell that seemed to get into your brain and make you feel that you could go up mountains at a run or wrestle with an elephant. She and Caspian said to one another, "I feel that I can't stand much more of this, yet I don't want it to stop." (16.17)
There is a sense of being almost, but not quite, overwhelmed by Aslan's power at the eastern end of the world.
And suddenly there came a breeze from the east, tossing the top of the wave into foamy shapes and ruffling the smooth water all round them. It lasted only a second or so but what it brought them in that second none of those three children will ever forget. It brought both a smell and a sound, a musical sound. Edmund and Eustace would never talk about it afterwards. Lucy could only say, "It would break your heart." "Why," said I, "was it so sad?" "Sad! No," said Lucy. (16.53)
As Edmund, Lucy, and Eustace get close to Aslan's country, they also get close to a place where all strong emotions seem to fuse together. Joy is heartbreaking.