Rosie and Tortoise by Margaret Wild
Rosie the hare is very excited about the imminent arrival of her new baby brother. But when he finally appears, he's so small and fragile that she is too scared even to hold him. Then Dad tells her a story about Tortoise who, slowly but surely, makes his way out of the forest, even though it's dark, because he has a little help from his friend, hare. Rosie realises that there is no need to worry about her little brother any more.