Sacrifice has been a part of the life of Christ's people since the days of Adam. After leaving the Garden of Eden Christ "gave unto them [Adam and Eve] commandments, that they should worship the Lord their God, and should offer the firstlings of their flocks, for an offering unto the Lord" (Moses 5:5).
In those days sacrifice was giving the best firstling of the flock to the Lord upon an altar. This was implemented in the beginning so the people of Christ would always have a reminder of the Lord's atoning sacrifice that would be made for them. It is for this reason other sacrifices were not pleasing to the Lord, as was the case with Cain, son of Adam.
"And in the process of time it came to pass that Cain brought of the fruit of the ground an offering unto the Lord ... But unto Cain, and to his offering, he [the Lord] had no respect" (Moses 5:19, 21).
Cain's offering of fruit was not a respectable offering because this offering was not the sacrifice they were commanded to give. The sacrifice of the firstling of the flock was a reminder of Christ, where as the fruit was not. Adam was taught this when an angel explained it to him:
"After many days an angel of the Lord appeared unto Adam, saying: Why dost thou offer sacrifices unto the Lord? ...This thing is a similitude of the sacrifice of the Only Begotten of the Father, which is full of grace and truth" (Moses 5:6-7).
Throughout the thousands of years before the Meridian of Time all prophets and people of God offered up these sacrifices. In these ancient times there were actually four types of sacrificial offerings. These offerings were explained by Elder Bruce R. McConkie as follows:
"Of all the Mosaic performances, none typified the atonement better than their sacrificial offerings. These were of four general kinds: 1, Burnt Offerings symbolized the entire surrender of the Lord's people to him and his laws. They were sacrifices in which a covenant of service and devotion was made. 2, Sin Offerings were the means whereby the whole congregation of Israel, based on repentance, was freed from sin... 3, Trespass Offerings were designed to cleanse individuals from particular sins, especially those committed through ignorance. This forgiveness was predicated upon repentance. 4, Peace Offerings were sacrifices of worship and adoration and gratitude to the Lord for the fellowship that existed between him and his people" (A New Witness of the Articles of Faith, McConkie, pg. 116).
The type of sacrifice made depended upon the reason for making the offering, but all of them were done with a firstling of the flock upon an altar.
The four sacrifices, or sacrificial offerings in general, were one of the key points of the Law of Moses. Moses was originally given the 'Higher Law,' which contained a different form of sacrifice, but due to the wickedness of the people he was required to present a simpler law, or the Law of Moses, in which these sacrifices were contained.
To understand the 'Higher Law' that contained a new form of sacrifice we must look to the teachings of Jesus of Nazareth himself during his mortal ministry on earth. One example of a time Jesus taught the higher law is when he gave what is commonly known as the Sermon on the Mount, found in the Holy Bible. Relatively few of the people in Jerusalem, however, listened and followed these teachings, but after his resurrection he visited a civilization in the Americas and taught them a similar sermon. This sermon can be found in the Book of Mormon, as written:
"Think not that I am come to destroy the law or the prophets. I am not come to destroy but to fulfill; For verily I say unto you, one jot nor one tittle hath not passed away from the law, but in me it hath all be fulfilled. And behold, I have given you the law and the commandments of my Father, that ye shall believe in me, and that ye shall repent of your sins, and come unto me with a broken heart and a contrite spirit. Behold, ye have the commandments before you, and the law is fulfilled.
"...Ye have heard that it hath been said by them of old time, and it is also written before you, that thou shalt not kill, and whosoever shall kill shall be in danger of the judgment of God; But I say unto you, that whosoever is angry with his brother shall be in danger of his judgment...
"Behold, it is written by them of old time, that thou shalt not commit adultery; But I say unto you, that whosoever looketh on a woman, to lust after her, hath committed adultery already in his heart...
"And again it is written, thou shalt not forswear thyself, but shalt perform unto the Lord thine oaths; But verily, verily, I say unto you, swear not at all; neither by heaven, for it is by God's throne; nor by the earth, for it is his footstool..." (3 Nephi 12:17-18, 21-22, 27-28, 33-35).
That is not everything spoken in this sermon, but it is enough to explain the point.
Christ had fulfilled the Law of Moses and it was time to implement the greater law among his people. Before it was "an eye for an eye" and now it is "turn the other cheek." Likewise the ways of sacrifice had changed. Before Christ's crucifixion the proper way of sacrifice was to give the first lamb of the flock to the Lord. The lamb in symbolism of the Lamb of God giving himself for the sins of the world. Now that this great sacrifice had been fulfilled, we are to sacrifice by serving the Lord with a broken heart and a contrite spirit, in remembrance of the life of Jesus Christ. This was also explained to the Nephites when Christ appeared to them.
"And ye shall offer up unto me no more the shedding of blood; yea, your sacrifices and your burnt offerings shall be done away, for I will accept none of your sacrifices and your burnt offerings.
"And ye shall offer for a sacrifice unto me a broken heart and a contrite spirit. And whoso cometh unto me with a broken heart and a contrite spirit, him will I baptize with fire and with the Holy Ghost" (3 Nephi 9:19-20).
What was once done to remember to look forward to Christ is now done to remember to look back at what he did. Elder Dallin H. Oaks, of the Quorum of the Twelve Apostles, has further explained it as thus:
"The incomprehensible suffering of Jesus Christ ended sacrifice by the shedding of blood, but it did not end the importance of sacrifice in the gospel plan. Our Savior requires us to continue to offer sacrifices... in effect, to offer a small imitation of His own sacrifice by making sacrifices of our own time and selfish priorities" (Oaks, Sacrifice).
As Christ Jesus spent the days of his mortal ministry serving people, so must we do now. He blessed the elderly, the children, those who had deficiencies. Whenever there was someone he could help, he helped. Not everyone on earth has the ability to give back sight, to heal lepers, to walk on water, but all people have the ability to visit a widow(er), to clean up a neighborhood, to get to know a lonely person. That is the kind of sacrifice we are asked to make now. To sacrifice our time and abilities to help those that we can.