I once heard someone say that we Christians are still bound to the observance of the Law given to Moses because Christ said the following in Matthew 5:18:
18: For verily I say unto you, Till heaven and earth pass, one jot or one tittle shall in no wise pass from the law, till all be fulfilled.
I woke up with this idea on my mind, (among many other thoughts), and as it happened, this very verse came up in my reading. Consider this:
The expression "Till heaven and earth pass" in English seems like a time adverbial phrase, or rather, it is a time adverbial. This is why some people legitimately read this phrase as the expiration date for the Law of Moses. Heaven and earth are still here, so they conclude, so must we observe the Law of Moses.
This phrase stirred my recollection of another phrase, "As The Lord liveth". Now this latter phrase was employed in Scripture as an expression denoting a commitment to accomplishing something with determination as solid as the fact that The Lord lives. It was at this moment that the expression "Till heaven and earth pass" came into greater focus:
Genesis 2:1-2
1: Thus the heavens and the earth were finished, and all the host of them.
2: And on the seventh day God ended his work which he had made; and he rested on the seventh day from all his work which he had made.
The heavens and earth, (this planet and its atmosphere, this entire biosphere), was what God had created. When He finished this great work of fashioning the earth and atmosphere and planting the flora and fauna, all in stages, various stages, He called His work completed, and He rested.
When Jesus came to the America's He delivered His Sermon on the Mount to the Nephites, His followers and covenant people here. This preaching is recorded in The Book of Mormon: Another Testament of Jesus Christ, 3 Nephi 12. This chapter, 3 Nephi 12, corresponds to Matthew 5, only notice this difference just before Jesus commands all to be perfect.
Matthew 5:46-48:
46: For if ye love them which love you, what reward have ye? do not even the publicans the same?
47: And if ye salute your brethren only, what do ye more than others? do not even the publicans so?
48: Be ye therefore perfect, even as your Father which is in heaven is perfect.
3 Nephi 12:46-48:
46: Therefore those things which were of old time, which were under the law, in me are all fulfilled.
47: Old things are done away, and all things have become гnew.
48: Therefore I would that ye should be perfect even as I, or your Father who is in heaven is perfect.
Jesus declared that all things had become new in Him. As all things had become new in Him, "all things" taken literally as regards this earth would indeed be "heaven and earth and all the host of them". Consequently, not one jot or tittle had passed away from the Law of Moses until the fulfillment took place, the fulfillment, that is, in Him.
This connection between what in The Bible may appear to be an as yet unreached expiration date, "till heaven and earth pass away", through the witness of The Book of Mormon: Another Testament of Jesus Christ becomes a clear reference to His work, a work Jesus was to fulfill, to end, and then He would declare all old things to be new.
At this moment some may feel to conclude that The Book of Mormon passages have cleverly reworked The Biblical passages. I urge the reader to consider the following:
Matthew 3:15:
15: And Jesus answering said unto him, Suffer it to be so now: for thus it becometh us to fulfill all righteousness. Then he suffered him.
Matthew 5:17:
17: Think not that I am come to destroy the law, or the prophets; I am not come to destroy, but to fulfill.
John 19:30:
30: When Jesus therefore had received the vinegar, he said, It is finished: and he bowed his head, and gave up the ghost.
2 Corinthians 5:17:
Therefore if any man be in Christ, he is a new creature; old things are passed away; behold, all things are become new.
Revelation 21:6:
6: And he said unto me, It is done [Lit: It occurred]. I am Alpha and Omega, the Beginning and the End. I will give unto him that is athirst of the fountain of the water of life freely.
From these Biblical passages we see that Christ came not to destroy the Law and the Prophets (the Scriptures), but to fulfill them. Just prior to His death on the cross He declared "It is finished", referring to the work of Redemption. Christ had yet to rise from the dead, but His Resurrection could only follow His Atonement for the sins of the world. At that precise moment when He had paid for our transgressions, He declared "It is finished". It was in this light that Paul later declared that "all things are become new", and this spiritual renewal will eventually cultimate in the heaven and earth being celestialized (Revelation 21).
But what of the heavens and earth being new? Outwardly there was no change, so how did the old heaven and earth pass as the renewal occurred? As it happens, among the Hebrews, especially as regards rejoicing over Redemption, the "heavens and earth" were symbolic of angel and man alike:
Deuteronomy 32:1:
1: Give ear, O ye heavens, and I will speak; and hear, O earth, the words of my mouth.
Isaiah 44:23-24:
23: Sing, O ye heavens; for The LORD hath done it: shout, ye lower parts of the earth: break forth into singing, ye mountains, O forest, and every tree therein: for The LORD hath Redeemed Jacob, and glorified Himself in Israel.
24: Thus saith The LORD, thy Redeemer, and He that formed thee from the womb, I am The LORD that maketh all things; that stretcheth forth the heavens alone; that spreadeth abroad the earth by Myself;
Micah 6:1-2:
1: Hear ye now what The LORD saith; Arise, contend thou before the mountains, and let the hills hear thy voice.
2: Hear ye, O mountains, The LORD's controvery, and ye strong foundations of the earth: for The LORD hath a controversy with his people, and He will plead with Israel.
These passages in Deuteronomy, Psalms, and Micah (among others) demonstrate the "heaven and earth" were used symbolically to represent angels and mankind alike. The Redemption of The Lord affected them, us, thus when He declared "It is finished" and later rose from the dead, "all became new", that is, reborn in Him, or through Him all could become redeemed.
So what may have looked like a clever Book of Mormon maneuvering of a Biblical passage on the duration of the Law of Moses actually fits together perfectly with that passage, that is, "till heaven and earth pass" does not mean "as long as this planet and its atmosphere exist" but "until I have completed the Redemption for angels and man alike". Other passages in The Bible that may not have seemed relevant alone now in light of what Jesus declared unto the Nephites come together in powerful relevance.
Now, the reader is, as always, at liberty to conclude for themselves. I ask what I always request, that be your conclusions however they may, remember that what I shared with you, at least, is actually textual.