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.

Wherever Abraham went, what was his practice?
I. What is said of the fifth commandment?
In what other prophecies is this same period mentioned?
What will be the standard in the judgment?
What power is there in the blood of this covenant?
Seeking a fair remuneration, what do many laborers do?
What has He promised to be to those in trouble?

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