That is quite obvious, but we are having a discussion in English. While Jesus of Nazareth generally spoke Aramaic, His words are recorded in Greek, and then translated into English.
So let's trace the use of the word "the law" in "the law of Moses" [meaning the Torah or the first five books of the Bible (also known as the Pentateuch)].
And he said unto them, These are the words which I spake unto you, while I was yet with you, that all things must be fulfilled, which were written in the law of Moses, and in the prophets, and in the psalms, concerning me. (Luke 24:44 KJV)
Εἶπε δὲ αὐτοῖς, Οὗτοι οἱ λόγοι, οὓς ἐλάλησα πρὸς ὑμᾶς ἔτι ὢν σὺν ὑμῖν, ὅτι δεῖ πληρωθῆναι πάντα τὰ γεγραμμένα ἐν τῷ νόμῳ* Μωσέως καὶ προφήταις καὶ ψαλμοῖς περὶ ἐμοῦ.
*Strong's Concordance (3551)
nomos: that which is assigned, hence usage, law
Original Word: νόμος, ου, ὁ
Part of Speech: Noun, Masculine
Transliteration: nomos
Phonetic Spelling: (nom'-os)
Definition: that which is assigned, usage, law
Usage: usage, custom, law; in NT: of law in general, plur: of divine laws; of a force or influence impelling to action; of the Mosaic law; meton: of the books which contain the law, the Pentateuch, the Old Testament scriptures in general.
So whatever Christ said in Aramaic was stated in the Greek as "the Law of Moses". And since there is no authority higher than Christ (who actually wrote the Ten Commandments with His own finger) then that should settle the matter.
It should also be noted here that Christ was putting His stamp of approval on the Hebrew canon (24 books) within the Tanakh. Those were split in several ways to produce 39 books in our OT. But the content is the same.
The Law of Moses = Torah = 5 books
The Prophets = Neviim = 8 books
The Psalms = Ketuvim = 11 books
The Apocrypha was automatically excluded.