The instruction Abel followed is written in the Garden of Eden...God's command and God making coats of skin for the man and woman after the sin. Abel agreed with and accepted God's command, he also acknowledge what sin has done in his offering, the firstborn of God's creation being born into death. Abel looked to the mercy seat or the being clothed in God that God showed when He made them coats of skin.
Abel looked to the covering that God provided. Cain followed the serpent's "Suit". Cain cut off Abel's bloodline when he murdered him, then they had Seth to replace him. And at that time men began to call on the Lord again.
Didn't you know that when God accepted Abel's offering that Abel was given passage to the Garden of Eden, to eat from the tree of life...Unless you think God accepted his offering and said "see ya around".
At the Passover the Israelites looked to and listened to what God said...Pharoah could only look to himself, which is the same thing I wrote in my first two sentences of my last post.