The Jewish community, from which Christianity sprang, has always understood the Torah to be both written (Sefer Torah) and oral (Torah She-B’al Peh):
Moses received the Torah from Sinai and gave
it over to Joshua. Joshua gave it over to the Elders, the Elders to the
Prophets, and the Prophets gave it over to the Men of the Great Assembly. They
[the Men of the Great Assembly] would always say these three things: Be
cautious in judgement. Establish many pupils. And make a safety fence around
the Torah. (Pirkei
Avot [Ethics of the Fathers] 1:1)
מֹשֶׁה קִבֵּל תּוֹרָה מִסִּינַי וּמְסָרָהּ לִיהוֹשֻֽׁעַ, וִיהוֹשֻֽׁעַ לִזְקֵנִים,
וּזְקֵנִים לִנְבִיאִים, וּנְבִיאִים מְסָרֽוּהָ לְאַנְשֵׁי כְנֶֽסֶת הַגְּדוֹלָה.
הֵם אָמְרוּ שְׁלֹשָׁה דְבָרִים: הֱווּ מְתוּנִים בַּדִּין, וְהַעֲמִֽידוּ תַּלְמִידִים
הַרְבֵּה, וַעֲשׂוּ סְיָג לַתּוֹרָה.