God remembers our distress

Genesis 38:1-30
Judah recognized them and said, "She is more righteous than I, since I wouldn't give her to my son Shelah."
When the time came for her to give birth, there were twin boys in her womb. As she was giving birth, one of them put out his hand; so the midwife took a scarlet thread and tied it on his wrest and said, "This one came out first." But when he drew back his hand, his brother came out, and she said, "So this is how you have broken out." And he was named Perez.
Judah's line: This extraordinary story is probably included because it forms part of the family tree of the royal house, from which the Messiah himself was descended. In planing it here, the editor points the contrast with Joseph's behaviour in Chapter 39
If a man die childless, his brother was duty bound to raise heirs to him by his widow.
Onan's action has nothing at all to do with contraception or masturbation: it has everything to do with rightful.
Tarmar' veil disguised her as a temple-prostitute. Festive times were linked with fertility生育 rites儀式 in Canaanite religion - and by his marriage Judah was mixed up with this.
Perez means breaking out. It was his line that led to David and so to Christ.
Zerah means scarlet or brightness.
Why?
Judah forgot his duty to his daughter-in-law, but Tarmar remember it, so God made the descendant line from her.
How?
People may forgive the right thing but God won't. God gives compassion to the weak person. God remembers our distress.