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 is Christ's second coming described in the Psalms?
What will be the fate of those who do not obey the gospel of Christ?
To another whose sight He had restored, what did Christ say?
What definite period is mentioned under this trumpet?
Are the angels interested in the plan of salvation?
12. What class of God's servants have evil angels, through wicked men, seemed to make special objects of attack?
In bereavement, like whom should we not sorrow?

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