Why did Yitzchak arrive early on the day of the wedding in Devil's Arithmetic?
Yitchak arrives early on the day of the wedding so that he and the children can help clean up the house. Shmuel will bring his new bride Fayge home to celebrate their wedding night, and Gitl wants things to be perfect for them. Gitl is a little uncomfortable because Shmuel's bride comes from a family that is from a higher social class than they are, and says,
"I will not have Fayge coming here, fresh from her father's house where there is a serving girl to clean, and think me and all in this shetl slovens."
Yitzchak responds by saying,
"That is exactly why I came early, Gitl, so I might help. My children too."
Yitzchak most likely has an ulterior motive for coming by early besides his declared intention of helping with the housecleaning. He is a widower with two small children, and would like Gitl to marry him. He shows his interest in her when he first comes in, greeting Shmuel but keeping his eyes on her, and is delighted to be offered some coffee, "eagerly" taking up the coffeepot that is offered to him and pouring himself a cup. Gitl on her part does not seem to be too willing to get involved with a man with two motherless children, and her ordinarily straightforward, gruff manner is even more imposing than usual, as she puts the coffeepot before Yitzchak with "a solid thwack," and parries his every comment with a not-so-gentle rebuttal. Nonetheless, Yitzchak's offer of help is much appreciated by the family, as he goes out to tend to the animals and his young children help with the chickens (Chapter 5).
In the book "The Devil's Arithmetic" Yitzchack is the town butcher. He also likes Gitl and wants to make an impression. He arrives early at the wedding to help to prepare for the wedding. He prepares the meats and he is also hoping to be able to be there when Gitl arrives.
He went to the house early arriving with cases of chickens as a gift. He has also come to help with the wedding preparations such as the house and getting it ready. He has brought his children along.