Where is commandment #129 found in the Bible?

This commandment is found in Deuteronomy 25:9, in the book of Deuteronomy.

Positive Commandment #129 of 613

A man must free the widow of his childless brother from the obligation to marry him if he is unwilling to marry her

Q: What is commandment #129 of the 613 commandments?

Commandment #129 is a positive commandment from Deuteronomy 25:9: "A man must free the widow of his childless brother from the obligation to marry him if he is unwilling to marry her." It belongs to the category of Marriage and Family.

Commandment #129 — a positive obligation from Deuteronomy 25:9, classified under Marriage and Family in the 613 commandments of the Torah.

Scripture

“then his brother's wife shall come to him in the sight of the elders, and pull his sandal off his foot and spit in his face; and she shall declare, 'Thus it is done to the man who does not build up his brother's house.'”

— Deuteronomy 25:9

Hebrew

ט וְנִגְּשָׁה יְבִמְתּוֹ אֵלָיו, לְעֵינֵי הַזְּקֵנִים, וְחָלְצָה נַעֲלוֹ מֵעַל רַגְלוֹ, וְיָרְקָה בְּפָנָיו; וְעָנְתָה, וְאָמְרָה, כָּכָה יֵעָשֶׂה לָאִישׁ, אֲשֶׁר לֹא-יִבְנֶה אֶת-בֵּית אָחִיו.

Greek (Septuagint)

9 καὶ προσελθοῦσα ἡ γυνὴ τοῦ ἀδελφοῦ αὐτοῦ ἔναντι τῆς γερουσίας καὶ ὑπολύσει τὸ ὑπόδημα αὐτοῦ τὸ ἓν ἀπὸ τοῦ ποδὸς αὐτοῦ καὶ ἐμπτύσεται εἰς τὸ πρόσωπον αὐτοῦ καὶ ἀποκριθεῖσα ἐρεῖ Οὕτως ποιήσουσιν τῷ ἀνθρώπῳ, ὃς οὐκ οἰκοδομήσει τὸν οἶκον τοῦ ἀδελφοῦ αὐτοῦ·