Genesis 38:28

And it came to pass, when she travailed, that the one put out his hand: and the midwife took and bound upon his hand a scarlet thread, saying, This came out first.

It should seem the birth was hard to the mother, by which she was corrected for her sin: the children also, like Jacob and Esau, struggled for the birth-right, and Pharez who got it, is ever named first, and from him Christ descended. He had his name from his breaking forth before his brother; this breach be upon thee - The Jews, as Zarah, bid fair for the birth-right, and were marked with a scarlet thread, as those that come out first; but the Gentiles, like Pharez, or a son of violence got the start of them, by that violence which the kingdom of heaven suffers, and attained to the righteousness which the Jews came short of: yet when the fulness of time is come, all Israel shall be saved. Both these sons are named in the genealogy of our Saviour, Matthew 1:3, to perpetuate the story, as an instance of the humiliation of our Lord Jesus.