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.

What, therefore, must he the character of His Word?
In all we do, whose glory should we have in view?
What reference is made in the Psalms to Christ's use of parables?
Who is the real power operating through the beast and his image, and demanding worship?
What other reason is given for keeping the Sabbath?
What is God called in the Scriptures?
How often did David say he would pray?

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