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 were the two on the way to Emmaus affected by Christ's conversation with them?
What has ever been the theme of God's prophets?
What is the first which He took away?
By what three distinct acts, then, was the Sabbath made?
6. What influence do the Bible and history show working in the church immediately after apostolic days?
What petition was made to the emperor by a church convention of bishops in AD 401?
How much do the dead know of what is going on among men?

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