“And in the process of time it came to pass that Cain brought an offering of the fruit of the ground to the Lord. Abel also brought of the firstborn of his flock and of their fat. And the Lord respected Abel and his offering, but He did not respect Cain and his offering. And Cain was very angry, and his countenance fell” (Genesis 4: 3-5)
When Cain brought his offering to the Altar, God was not pleased with him or his offering. Why? The truth is that Cain could have made an effort for the Altar, much more than what he did, and God knew this. God, Himself, reproved Cain and he knew that this would reflect in his life so that was the reason his countenance fell. His work, his future and everything in his life was destined for failure; after all, he displeased the Almighty, the only One Who could bless every aspect of his life.
In Abel’s case, God was pleased with him and what he offered on the Altar, because Abel made a real sacrifice. His sacrifice was excellent – perfect – so he left the Altar different to his brother, knowing that his work and his entire future were in the hands of God.
Both, Abel and Abraham, were tested and approved and, they overcame. On the other hand, Cain was not accepted.
“…To him who overcomes I will give some of the hidden manna to eat. And I will give him a white stone, and on the stone a new name written which no one knows except him who receives it” (Revelation 2: 17)