How did Abel know to offer a lamb as sacrifice? He was a prophet!
Matthew 23:34-36
New King James Version (NKJV)
34 Therefore, indeed, I send you prophets, wise men, and scribes: some of them you will kill and crucify, and some of them you will scourge in your synagogues and persecute from city to city, 35 that on you may come all the righteous blood shed on the earth, from the blood of righteous Abel to the blood of Zechariah, son of Berechiah, whom you murdered between the temple and the altar.
Scripture says Abel was a prophet. He understood that the lamb that was slain in the Garden of Eden to clothe Adam and Eve was a "parallel", or picture of an acceptable blood sacrifice. I don't doubt the Holy Spirit revealed this to Abel.
The shed blood of the lamb is a parallel to the ultimate acceptable sacrifice. Jesus.
In earlier posts, I pointed out to the suffering of the prophets and Abel was no exception insofar as he was killed by his brother. He understood (by revelation of the Holy Spirit) that sacrifice required the shedding of blood. His brother thought he knew a better way so he offered something that he grew in the field.
Man today is a lot like Cain. He doesn't care what God reveals. He doesn't care what is acceptable to the Lord. He chooses to worship any way he wants. Or he chooses not to worship the One True God at all.
YBIC
Bruce Baber