Now one autumn morning when the wind had blown all the leaves off the trees in the night, and was trying to blow the branches off, Pooh and Piglet were sitting in the Thoughtful Spot and wondering.
"What I think," said Pooh, "is I think we'll go to Pooh Corner and see Eeyore, because perhaps his house has been blown down, and perhaps he'd like us to build it again."
"What I think," said Piglet, "is I think we'll go and see Christopher Robin only he won't be there, so we can't."
"Let's go and see everybody," said Pooh. "Because when you've been walking in the wind for miles, and you suddenly go into somebody's house, and he says, 'Hallo, Pooh, you're just in time for a little smackerel of something,' and you are, then it's what I call a Friendly Day."
Piglet thought that they ought to have a Reason for going to see everybody, like Looking for Small or Organizing an Expotition, if Pooh could think of something.
Pooh could.
"We'll go because it's Thursday," he said, "and we'll go to wish everybody a Very Happy Thursday. Come on, Piglet."
They got up; and when Piglet had sat down again, because he didn't know the wind was so strong, and had been helped up by Pooh, they started off. They went to Pooh's house first, and luckily Pooh was at home just as they got there, so he asked them in, and they had some, and then they went on to Kanga's house, holding on to each other, and shouting, "isn't it?" and "What?" and "I can't hear".
This is from "The House At The Pooh Corner". Because they (Pooh and Piglet) went to Pooh's house, why could Pooh be at home and ask them in?