Moses 5

After being cast out of the Garden of Eden, Adam heard the voice of the Lord and -

"...he gave unto them commandments, that they should worship the Lord their God, and should offer the firstlings of their flocks, for an offering unto the Lord." (Pearl of Great Price Moses 5:5)

I think this must have been a very interesting commandment for Adam. It wasn't just that he had to sacrifice the first born male of each sheep, which must have been somewhat difficult to say the least, but this also meant that he had to keep track of all his sheep knowing if it was the firstling or not. It seems from the beginning that some sort of record must have been kept.

And with must have been a somewhat confusing commandment, we read -

"...And Adam was obedient unto the commandments of the Lord." (Pearl of Great Price Moses 5:5)

If there is any question whether and Adam and Eve had faith, it is obvious he did. It was sometime later for -

"...after many days an angel of the Lord appeared unto Adam, saying: Why dost thou offer sacrifices unto the Lord? And Adam said unto him: I know not, save the Lord commanded me." (Pearl of Great Price Moses 5:6)

The Lord doesn't leave His children in the dark forever for it was revealed -

"This thing is a similitude of the sacrifice of the Only Begotten of the Father, which is full of grace and truth.
8 Wherefore, thou shalt do all that thou doest in the name of the Son, and thou shalt repent and call upon God in the name of the Son forevermore." (Pearl of Great Price Moses 5:7 - 8)

"And in that day the Holy Ghost fell upon Adam, which beareth record of the Father and the Son, saying: I am the Only Begotten of the Father from the beginning, henceforth and forever, that as thou hast fallen thou mayest be redeemed, and all mankind, even as many as will." (Pearl of Great Price Moses 5:9)

This is the gospel, the glorious news. But note that before the Holy Ghost fell on Adam, he had to be obedient. It was after being obedient with faith, having then been giving more knowledge that -

"Adam blessed God and was filled, and began to prophesy concerning all the families of the earth, saying: Blessed be the name of God, for because of my transgression my eyes are opened, and in this life I shall have joy, and again in the flesh I shall see God.
11 And Eve, his wife, heard all these things and was glad, saying: Were it not for our transgression we never should have had seed, and never should have known good and evil, and the joy of our redemption, and the eternal life which God giveth unto all the obedient.
12 And Adam and Eve blessed the name of God, and they made all things known unto their sons and their daughters." (Pearl of Great Price Moses 5:10 - 12)

Happiness and joy follow as we keep His commandments.

"Adam fell that men might be; and men are, that they might have joy." (Book of Mormon 2 Nephi 2:25)