I was studying today and had a question come up that I didn't really know what to do with, so I thought I'd take advantage of your invitation to check some of our questions out with you.
I was reading in Moses 5 ... Cain and Abel brought their sacrifices before the Lord, Abel with exact obedience according the commandments ... while Cain brought a sacrifice, but not one authorized by the Lord ... and it was consequently not accepted of the Lord, and Cain became wroth and his countenance fell. What does that mean?
Another question derives from verse 23. The Lord had spoken to him and asked, "Why art thou wroth, why is thy countenance fallen... If thou doest well, thou shalt be accepted..." ... Was the Lord merely warning Cain not to get offended, to go his way and sin no more, but if he wouldn't, the inability to take counsel from the Lord would allow Satan to have him?
Cain loved Satan and united with him in secret, killing Abel, and then the Lord came again and said to him: "Whosoever slayeth thee, vengeance shall be taken on him sevenfold. And I the Lord set a mark upon Cain, lest any finding him should kill him." Why was he to an extent "preserved"? The Lord cursed those that would try to kill him and set a mark on him, lest any would try. Why?
"... Abel hearkened unto the voice of the Lord. And Abel was a keeper of sheep, but Cain was a tiller of the ground. And Cain loved Satan more than God. And Satan commanded him, saying: Make an offering unto the Lord. And in process of time it came to pass that Cain brought of the fruit of the ground an offering unto the Lord. And Abel, he also brought of the firstlings of his flock, and of the fat thereof. And the Lord had respect unto Abel, and to his offering; But unto Cain, and to his offering, he had not respect. Now Satan knew this, and it pleased him. And Cain was very wroth, and his countenance fell." (Moses 5:17-21)The ordinance of sacrifice was a prototype (or symbol) of the sacrifice of the Lamb of God. So, Cain's sacrifice was unacceptable for two very important reasons: (1) by offering the fruits of the ground he was mocking an approved ordinance, something like administering the sacrament with carrots and broccoli--on purpose; (2) above all, even if it had been performed correctly, Cain's sacrifice was offered not in obedience to God's commandment, but following Satan's instructions. The Lord stated:
"Behold, mine house is a house of order, saith the Lord God, and not a house of confusion. Will I accept of an offering, saith the Lord, that is not made in my name? Or will I receive at your hands that which I have not appointed? And will I appoint unto you, saith the Lord, except it be by law, even as I and my Father ordained unto you, before the world was?" (D&C 132:8-11)The Lord knew what was about to happen, and how Satan would tempt Cain. Remember the following: "... all things have been done in the wisdom of him who knoweth all things." (2 Nephi 2:24) "My name is Jehovah, and I know the end from the beginning" (Abraham 2:8). So, the Lord warned Cain (we don't know exactly how; it might have been directly or by a revelation given to through Adam) that Satan was trying to get him.
As to Cain's countenance "falling," I don't know what that means, but my reading of the scriptures suggest that it might have something to do with losing the light of Christ and instead displaying anger, hatred, etc., effects of a "fallen" condition. The following scriptures are the basis for this interpretation:
"Moreover when ye fast, be not, as the hypocrites, of a sad countenance: for they disfigure their faces, that they may appear unto men to fast ..." (Matthew 6:16)
"And inasmuch as ye do these things with thanksgiving, with cheerful hearts and countenances, not with much laughter, for this is sin, but with a glad heart and a cheerful countenance" (D&C 59:15)
The idea of Cain ruling over Satan is simple: in the resurrection Cain will have a perfect, immortal body whereas Satan will continue being a spirit forever. The prophet Joseph Smith taught:
"The great principle of happiness consists in having a body. The devil has no body, and herein is his punishment. All beings who have bodies have power over those who have not." (Teachings, p.181)Elder Joseph Fielding Smith presented the following reasoning:
"As far as Cain is concerned, the information given is definite that he became Perdition, and that Lucifer who is Satan, became subject to him. It appears that the reason Satan desired to have him was due to the fact that Cain had obtained a body of flesh and bones and therefore had superior power, and Satan was willing to accept and be obedient to him because of that condition. The natural conclusion is, therefore, that a devil with a body of flesh and bones has some power greater than one who was denied the physical body." (Answers to Gospel Questions, Vol.2, p.172)
Now let's deal with Cain's preservation from revenge. Remember that at the time Cain and Abel were born, Adam and Eve were already grandparents, since their non-believing children had already begun to marry among themselves.
"And Adam knew his wife, and she bare unto him sons and daughters, and they began to multiply and to replenish the earth. And from that time forth, the sons and daughters of Adam began to divide two and two in the land, and to till the land, and to tend flocks, and they also begat sons and daughters." (Moses 5:2-3)After many days an angel explained the plan of salvation to Adam; then, the following happened:
"And Adam and Eve blessed the name of God, and they made all things [i.e. the plan of salvation] known unto their sons and their daughters. And Satan came among them, saying: I am also a son of God; and he commanded them, saying: Believe it not; and they believed it not, and they loved Satan more than God. And men began from that time forth to be carnal, sensual, and devilish." (Moses 5:12-13)Then, probably heartbroken with the unbelief of their children and grandchildren, the first couple decides to try again to have a righteous posterity:
"And Adam and Eve, his wife, ceased not to call upon God. And Adam knew Eve his wife, and she conceived and bare Cain, and said: I have gotten a man from the Lord; wherefore he may not reject his words. But behold, Cain hearkened not, saying: Who is the Lord that I should know him? And she again conceived and bare his brother Abel. And Abel hearkened unto the voice of the Lord. ..." (Moses 5:16-17)
The idea of placing some kind of visible mark (ancient Jewish rabbis believed that it was leprosy) upon Cain to prevent his assassination might (I said "might") have been an effort to avoid endless "vendettas" perpetrated by his older siblings and relatives. This could have turned into a pre-Flood version of the "Hatfield & McCoy" family feud.