Nothing in the Law or the Prophets can EVER change. 

Deuteronomy 4:2 ASV
(2)  Ye shall not add unto the word which I command you, neither shall ye diminish from it, that ye may keep the commandments of Jehovah your God which I command you.

Deuteronomy 5:32 ASV
(32)  Ye shall observe to do therefore as Jehovah your God hath commanded you: ye shall not turn aside to the right hand or to the left.

Numbers 15:40 ASV
(40) that ye may remember and do all my commandments, and be holy unto your God.

Heaven and earth shall pass away, but my words shall not pass away.  Matthew 24:35 ASV

If we understand that nothing in the Bible can change, we can easily shield ourselves against false doctrines.

Before the Advent of Jesus, the cardinal rule in Moses is that there cannot be any going around what God (Jesus) commanded in Moses nor any adding to it or taking away from it.

Ye shall observe to do therefore as Jehovah your God hath commanded you: ye shall not turn aside to the right hand or to the left.  Deuteronomy 5:32 ASV

What thing soever I command you, that shall ye observe to do: thou shalt not add thereto, nor diminish from it.  Deuteronomy 12:32 ASV

(17) Think not that I came to destroy the law or the prophets: I came not to destroy, but to fulfil.  (18)  For verily I say unto you, Till heaven and earth pass away, one jot or one tittle shall in no wise pass away from the law, till all things be accomplished. Matthew 5:17-18 ASV

For whosoever shall keep the whole law, and yet stumble in one point, he is become guilty of all.  James 2:10 ASV

With Jesus, the cardinal rule of strict adherence to Moses and the Prophets remains.
Jesus (God) asserted in Matthew 5:17-18 the same principle of the unchangeable nature of Moses and the Prophets. He even added that it is more possible that our world can disappear than one character in the alphabet of the letters in Moses to ever change.

Nevertheless, we discard the dogma of immutability of Moses and the Prophets to entertain and adopt changes which men have succeeded in establishing in the faith of the majority of believers in God (Jesus) to lead them to perdition.

Faced with the rejection of the Israelites of Moses, God (Jesus) did not make adjustments to Moses to bring the Law to par with the trends of time. The only difference then and now is the fulfillment of the rites of which the body of Jesus (God) was the shadow of the actual killings of the Lamb.

If we're missing just 1 commandment in our belief system, we will not be saved because we are not without sin, that is, we are not holy. The grace of Jesus is for the holy ones, according to Ezekiel 33:13-20.

Ezekiel 33:13 ASV
(13)  When I say to the righteous, that he shall surely live; if he trust to his righteousness, and commit iniquity, none of his righteous deeds shall be remembered; but in his iniquity that he hath committed, therein shall he die.