How early was this sacrificial system known?

Answer

"By faith Abel offered unto God a more excellent sacrifice than Cain, by which he obtained witness that he
was righteous, God testifying of his gifts." Heb. 11: 4. See Gen. 4: 3-5; 8: 20.

How willing is God to give to us the Holy Spirit?
What call was made to come out of Babylon?
By what means did the Jews know God's will?
What did Constantine's law require?
18. Answering the question as to what would be the sign of His coming and the end of the world, what did Christ say?
How was Christ strengthened after His forty days' fast and temptation in the wilderness?
In what one promise are all these promises summed up?

Questions & Answers are from the book Bible Readings for the Home Circle