Babylonian Talmud Makkot 23b-24a:
R. Simlai when preaching said: Six hundred and thirteen precepts were communicated to Moses, three hundred and sixty-five negative precepts, corresponding to the number of solar days [in the year], and two hundred and forty-eight positive precepts, corresponding to the number of the members of man's body.
Said R. Hamnuna: What is the biblical source for this? It is: "Moses commanded us torah, an inheritance of the congregation of Jacob," (Deuteronomy 33:4). "Torah" being, in numerology, equal to six hundred and eleven, "I am" and "Thou shalt have no [other Gods]" (Exodus 20:2-3) [not being reckoned, because] we heard from the mouth of the Might [Divine].
Authority of Sages through generations to create and interpret law:
Babylonian Talmud Shabbat 23a:
What benediction is uttered [0ver the Hanukkah lights]?
--This: "Who sanctified us by His commandments and commanded us to kindle the light of Hanukkah.
And where did He command us? -R. Awia said: [It follows] from, "thou shalt not turn aside [from the sentence Which they shall shew thee]".( Deuteronomy 17:11).
R. Nehemiah quoted: "Ask thy father, and he will shew thee; Thine elders, and they will tell thee" (Ibid. 32:7.
Tanhuma Ki Tissa 34 (ed. Buber, 17):
"And the Lord said unto Moses: Write thou these words" (Exodus 34:27).
This is what Scripture said: "Though I write for him never so many things of my Law, they are accounted as a stranger's" (Hosea 8:12)Š
When the Holy One came to give the Torah, he dictate it to Moses in order: The Bible, the Mishnah, the Aggadah and the Talmud. For it says "God spoke all these words" (Exodus 20:1)Š
Said R' Judah bar Shalom: When the Holy One said to Moses "Write thou," Moses wanted the Mishnah to be written down. However, because the Holy One foresaw that the nations of the world would one day translate the Torah and read it in Greek, and that they would declare "we are Israel!"
So far the scales are evenly balanced.
The Holy One said to the nations: You claim that you are my children? I do not know. However, I those who are in possession of my mystery are my children. And what is that? It is the Mishnah that was given orally, and everything is left up to you to expound.
Said R' Judah bar Shalom: The Holy One said to Moses: What is it that you want? That the Mishnah should be in written form? Then what would be the difference between Israel and the nations.
For it is said: "Though I write for him never so many things of my Law"-- If so, then: "they are accounted as a stranger's."
Instead, let them have the Scripture in written form and the Mishnah in oral form.
"Write thou these words"-- referring to Scripture.
"For after the tenor of these words I have made a covenant with thee and with Israel" referring to oral Mishnah.
Babylonian Talmud Menahot 29b:
Rab Judah said in the name of Rab:
When Moses ascended on high he found the Holy One, blessed be He, engaged in affixing coronets to the letters.
Said Moses, "Lord of the Universe, Who stays Thy hand?"
He answered, "There will arise a man, at the end of many generations, Akiba b. Joseph by name, who will expound upon each tittle heaps and heaps of laws".
"Lord of the Universe", said Moses; "permit me to see him".
He replied, "Turn thee round". Moses went and sat down behind eight rows [and listened to the discourses upon the law].
Not being able to follow their arguments he was ill at ease, but when they came to a certain subject and the disciples said to the master "Whence do you know it?" and the latter replied "It is a law given unto Moses at Sinai" he was comforted.
relationships to Halakah: filling gaps, evolving into halakhah, regulated by halakhah.