Deuteronomy 21:17

כִּי֩ אֶת־הַבְּכֹ֨ר בֶּן־הַשְּׂנוּאָ֜ה יַכִּ֗יר לָ֤תֶת לוֹ֙ פִּ֣י שְׁנַ֔יִם בְּכֹ֥ל אֲשֶׁר־יִמָּצֵ֖א ל֑וֹ כִּי־הוּא֙ רֵאשִׁ֣ית אֹנ֔וֹ ל֖וֹ מִשְׁפַּ֥ט הַבְּכֹרָֽה׃ ס

άλλὰ τὸν ἀλλὰ τὸν πρωτότοκον υἱὸν τῆς μισουμένης ἐπιγνώσεται δοῦναι αὐτῷ διπλᾶ ἀπὸ πάντων ὧν ἂν εὑρεθῇ αὐτῷ, ὅτι οὗτός ἐστιν ἀρχὴ τέκνων αὐτοῦ, καὶ τούτῳ καθήκει τὰ πρωτοτοκεῖα.

Greek text from Swete's edition, CC BY-SA 4.0

Mas al hijo de la aborrecida reconocerá por primogénito, para darle dos tantos de todo lo que se hallare que tiene: porque aquél es el principio de su fuerza, el derecho de la primogenitura es suyo.

Instead, he must acknowledge the firstborn, the son of his unloved wife, by giving him a double portion of all that he has. For that son is the firstfruits of his father ’s strength; the right of the firstborn belongs to him. A Rebellious Son (Luke 15:11–32)