mP, NC have explained Mosaic Law pretty well. Allow me to add my 2 cents.
Mosaic Law is essentially a covenant or binding contract between the nation Israel and God. Its provisions were to separate or essentially differentiate Israel from the other nations at that time, a special people who were to be a light to the nations. A role which Israel has spectacularly failed to fulfill. Essentially the Mosaic Law wasn't as much as it was designed to punish people, but instead it serves as a guidepost to show how hard it is to reach God's standards.
In Jesus' time, the Mosaic Law have already evolved into a huge mess of convoluted legalistic interpretations, rules and regulations. Jesus indicted them in Mark 7, saying the following:
6 He answered and said unto them, Well hath Esaias prophesied of you hypocrites, as it is written, This people honoureth me with their lips, but their heart is far from me.
7 Howbeit in vain do they worship me, teaching for doctrines the commandments of men.
8 For laying aside the commandment of God, ye hold the tradition of men, as the washing of pots and cups: and many other such like things ye do.
9 And he said unto them, Full well ye reject the commandment of God, that ye may keep your own tradition.
10 For Moses said, Honour thy father and thy mother; and, Whoso curseth father or mother, let him die the death:
11 But ye say, If a man shall say to his father or mother, It is Corban, that is to say, a gift, by whatsoever thou mightest be profited by me; he shall be free.
12 And ye suffer him no more to do ought for his father or his mother;
13 Making the word of God of none effect through your tradition, which ye have delivered: and many such like things do ye.
14 And when he had called all the people unto him, he said unto them, Hearken unto me every one of you, and understand:
15 There is nothing from without a man, that entering into him can defile him: but the things which come out of him, those are they that defile the man.
16 If any man have ears to hear, let him hear.
Which is why Jesus said in Matt 11:28-30 that He offers respite from the onerous burden of the Mosaic Law.
28 Come unto me, all ye that labour and are heavy laden, and I will give you rest. 29 Take my yoke upon you, and learn of me; for I am meek and lowly in heart: and ye shall find rest unto your souls. 30 For my yoke is easy, and my burden is light.
Note: Notice the bolded verses. This indictes the blood doctrine that WT has been shoving down the throats of the R&F.
