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.

Upon what ground does God's work for sinners rest?
What does the imputed righteousness of Christ enable God to do, and still be just?
By what comparison is it shown that the heavenly sanctuary will he cleansed?
4. What was another memorial instituted to commemorate another signal providence in behalf of the Israelites?
Do they take any part in earthly things?
In ministering to the needy, whom are we really serving?
How much of the land of Canaan did Abraham own in his lifetime?

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