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.

Of what is Christian baptism an evidence?
Upon what basis is justification granted?
How has Christ made it possible for righteousness to be imputed to the believer?
18. What effect did Christ's miracles have upon the individuals restored, and the people who witnessed them?
What did Daniel say the king had seen in his dream?
Why did the Lord abhor the Canaanites?
For what did Job say he would wait after death?

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