Passover Offering in Genesis
Yahweh made known to Adam and his progeny that they could please Him through sacrifices. Now, outside the garden, the two sons brought special sacrifices:
And in process of time it came to pass, that Cain brought of the fruit of the ground an offering unto Yahweh. And Abel, he also brought of the firstlings of his flock and of the fat thereof. And Yahweh had respect unto Abel and to his offering: But unto Cain and to his offering He had not respect. And Cain was very wroth, and his countenance fell. And Yahweh said unto Cain, Why are you wroth? And why is your countenance fallen? If you do well, shall you not be accepted? And if you do not well, sin lies at the door. And unto you [shall be] his desire, and you shall rule over him. (Gen. 4:3-7)
Notice the account starts with the statement, 'In the process of time it came to pass…' The Hebrew reads, 'At the end of days.' The sense is that time went along and suddenly a special event arrived. Something important was about to take place that some Bible scholars maintain was the time of the first Passover.
Notice that Cain brought of the fruit of the ground, crops that he had raised and harvested. His offering was the works of his hands. Abel, on the other hand, brought of the firstlings of his flock. Not only did he bring firstlings but he also brought something extra: the fat of the animals, which was really not required.
Abel brought the proper sacrifices above what apparently Yahweh required. Notice the difference: Cain brought what he had harvested, the works of his own hands. Abel approached Yahweh through the blood of the lamb, a sacrificial animal! Obviously this pointed toward the Passover sacrifice, and ultimately to the death of Yahshua the Messiah. Blood was shed in Abel's sacrifice as he came before Yahweh. No wonder we read the following commendation in the faith chapter:
By faith Abel offered unto Elohim a more excellent sacrifice than Cain, by which he obtained witness that he was righteous, Elohim testifying of his gifts: and by it he being dead yet speaks. (Heb. 11:4)
In his human effort to reconcile himself to Yahweh, Abel acted out the Passover sacrifice by offering a sacrificial lamb. Cain perhaps arrogantly brought a harvest or Feast of Tabernacles offering, the last feast of the year, ignoring all other annual Feasts.
It should also be pointed out that Yahweh Himself made garments of skins of animals whereby He clothed Adam and Eve after they had made themselves aprons of fig leaves to cover themselves. Thus, Yahweh sacrificed animals, shedding their blood, to cover Adam and Eve's nakedness with animal skins.
This is a type, indicating that Yahweh will ultimately provide His people with special garments acceptable to Him. Yahweh clothes His saints with the garments of salvation:
I will greatly rejoice in Yahweh, my soul shall be joyful in my Elohim; for He has clothed me with the robe of righteousness, as a bridegroom decks himself with ornaments, and as a bride adorns herself with her jewels. (Isa. 61:10)
Note the 'garments of salvation' are also described as 'robes of righteousness,' which are put on those who obey Yahweh's laws and accept His Son as the propitiation for our sins.
And I said unto him, Sir, you know. And he said to me, these are they which came out of great tribulation, and have washed their robes, and made them white in the blood of the Lamb. (Rev. 7:14)