We are commanded to follow the decisions of the Sanhedrin and it is forbidden not to do so, as it says "[You shall do according to the thing they tell you... you shall do] according to the Torah they teach you and the judgment they tell you; you shall not depart from the thing they tell you left or right".¹ A sage who refuses to accept their decision and continues to rule otherwise is called a "rebellious elder" and must be put to death, as it says "And the man who acts wilfully not to listen... to the judge, that man shall die."² When there is no Sanhedrin a person must follow the courts of his generation, as it says "[And you shall come...] to the judge that exists in those days".³ If courts disagree one should follow the more stringent view; but in cases involving rabbinical law one can follow the more lenient view.^a

It is forbidden to add or subtract from the Torah, as it says "[Everything that I command you, you shall be careful to do;] you shall not add to it and you shall not take away from it".⁴ However, the courts can make new laws or extend the laws of the Torah as long as there is no conflict with the Torah; and they can even abrogate parts of the Torah temporarily when necessary.^b

We are commanded to honor our parents and to stand in awe of them, as it says "Honor your father and your mother",⁵ and it says "Each shall fear his mother and his father".⁶ There are special prohibitions against cursing or striking them, as it says "[For any man who curses his father or his mother shall be put to death;] he cursed his father or mother, his blood is on him",⁷ and it says "And one who strikes his father or mother shall be put to death... [and one who curses his father or mother shall be put to death]".⁸ A rebellious son can be executed [as it says "And if a man has a rebellious son..."].^9,c

Sources:
1. Deut. 17:10-11	a. 1:1-2,5; 2:1; 3:4
2. Deut. 17:12	b. 2:4-5,9
3. Deut. 17:9	c. 5:1,5; 6:1; 7:1
4. Deut. 13:1
5. Ex. 20:12; Deut. 5:16
6. Lev. 19:3
7. Lev. 20:9
8. Ex. 21:15,17
9. Deut. 21:l8ff