Midras Kejadian 38:28: Ein Yaakov (Glick Edition) & Bereshit Rabbah

Because she had covered her face did he think her a harlot? [Is it not the contrary?] R. Elazar said that this means: She had covered her face when she had been in his house, hence he did not know her." Therefore she was rewarded that from her descended kings and prophets — kings from David; and prophets, as R. Levi said: "A bride who is chaste in the house of her father-in-law, will be rewarded that kings and prophets will descend from her." Whence do we infer this? From Tamar When she was lead forth she sent to her father-in-law. The text should have the word Meutzeas, in the passive voice [instead of Motzes in the active voice]. R. Elazar said: This means that after she produced the signs [of the signet, scarf and staff], the Angel Samael came and removed them, then the Angel Gabriel came and brought them again and this is the meaning of the passage (Ps. 56 1) To the chief musician upon Joneth elem-re-chokin." Said R. Jochanan: "This means that after the signs were removed she became numb like a dove." (Ib., ib., ib.) Unto David a Michtam, i.e., of whom David went forth, who kept himself humble and plain to everyone. Could Michtam be explained in another way that he was born circumsized? Can Michtam be explained in another way that just when in his youth he humbled himself before a superior in order to study the Torah from him, so also when he was elevated, he kept himself meek before one who was greater than he in order to study the Torah? (Ib., ib.) And she sent to her father-in-law, saying, 'By the man who owns these,' etc., why did she not call him by his name? Said Mar Zutra b. Tubia in the name of Rab; others say R. Chana b. Bizna said in the name of R. Simon, the pious; still others say R. Jochanan said it in the name of R. Simon b. Jochai: "It is better for a man to be thrown into a fiery furnace than be the means of bringing another to shame in public. We infer this from Tamar." (Gen. 38, 25) (Ib., ib., ib.) Acknowledge I pray thee. Said R. Chama b. Chanina: "With the word Haker (acknowledged) did Juda inform his father [concerning Joseph's disappearance] and with the word Haker (acknowledge) was Juda informed of the bad tidings [concerning the affair of Tamar]; i.e., with the word Haker did Juda inform his father, (Ib. 37. 32) Hakerna (acknowledge), we pray thee, whether it be thy son's coat or not, and with the word Haker was Juda informed Haker (acknowledge) I pray thee to whom belong the signet, scarf, and staff!" Acknowledge, I pray thee, the word Nah means nothing else but pray. She thus said unto Juda: "I pray thee acknowledge thy Creator and do not avert thy eyes from me." And Juda acknowledged them. And this is meant by R. Chama b. Bizna, who said in the name of R. Simon the pious: "Joseph, who sanctified Heaven's name in secret was rewarded with only one additional letter of the name of the Holy One, praised be He, as it is written (Ps. 81) but Juda, who sanctified Heaven's name publicly was rewarded so that his entire name was equal to that of the Holy One, praised be He." As soon as he confessed and said, a Divine voice went forth and said: "Thou hast saved Tamar with her two children from being burnt in fire, I swear by thy life that I shall save through thy merits thy three sons from being burnt in fire." Who are they? Chanania, Mishael and Azaria. She it righteous, it is from me. How did he know it? A Divine voice went forth and said: "From me went forth the secret things." (Ib., ib., ib.) Said Samuel the senior, the father-in-law of R. Samuel b. Ama: "This means that since he knew her he never forsook her, for it is written (Deut. 5, 19) A great voice v'lo yassph. [Just as in the latter case it means for ever, so also does it mean in the former case] ."

“It was at the time of her giving birth, and, behold, there were twins in her womb” (Genesis 38:27).
“It was at the time of her giving birth” – here they were incomplete, but elsewhere they were complete.⁵⁶Regarding Rebecca’s birth of Jacob and Esau it is written: “Her days to give birth were complete” (Genesis 25:24).
“Behold there were twins [teomim] in her womb” – teomim is written complete, as here they were both righteous. Elsewhere tomim (Genesis 25:24) is written, incomplete, as one was righteous and one was wicked.⁵⁷Regarding the birth of Jacob and Esau, the word for twins is written without an alef, so that it is read tomim rather than teomim. This is because only Jacob was righteous.
“It was as she was giving birth, one extended a hand; the midwife took and bound upon his hand a crimson thread, saying: This one emerged first” (Genesis 38:28).
“It was as she was giving birth, one extended a hand” – Rava bar Rav Ḥisda said: There are three who are believed immediately, and these are: The midwife, the caravan, and a woman who attests to the purity of another woman. Midwife – as it is written: “The midwife took and bound upon his hand a crimson thread, saying: This one emerged first.” Caravan – as Rabbi Simon brother of Rabbi Yehuda bar Zavdi said in the name of Rav: A child, as long as he is cast in the street, his father and mother can testify in his regard. When he is gathered from the street, he requires two witnesses.⁵⁸If a young child is abandoned in the street, and adults come and claim to be his parents who were passing by in a caravan and lost their child, they are believed. But if the child has already been taken in from the street, testimony is required to establish the relationship between the child and individuals who claim to be his parents. See also Kiddushin 73b. And a woman who attests to the purity of another woman – as we learned: If three women were sleeping in one bed and there was blood under one of them, they are all impure. If one of them examined herself and found blood, she alone is impure. Rava said: Provided that it is within twenty-four hours.