Genesis 4:3–5 — So it came about in the course of time that Cain brought an offering to the LORD of the fruit of the ground. 4 Abel, on his part also brought of the firstlings of his flock and of their fat portions. And the LORD had regard for Abel and for his offering; 5 but for Cain and for his offering He had no regard. So Cain became very angry and his countenance fell.
In our previous reflection, we made the argument that the command to keep the sabbath holy existed from the time that God gave us the example of resting on the seventh day of the creation week. We determined this by considering the way in which the 4th Commandment is worded in Exodus 20:9-11.
In this meditation and the next one, we want to see that the Scriptures support this contention in at least two accounts of events that took place before the Law was give on Mount Sinai.
Note in the passage above that Cain and Abel brought offerings to God "in the course of time." The literal reading in the marginal notes of the New American Standard Bible for this phrase reads, "at the end of days." A.W. Pink, in his book, "Gleanings in Genesis," makes the following point here:
The marginal reading of Genesis 4:3 gives, "And at the end of days it came to pass, that Cain brought of the fruit of the ground an offering unto the Lord." May not this signify, at the end of the week? In other words, does not this expression appear to point to the Sabbath day as the time when God was to be formally worshipped?
Matthew Henry agrees that this is an acceptable understanding of this passage:
In process of time, when they had made some improvement in their respective callings (Heb. At the end of days, either at the end of the year, when they kept their feast of in-gathering or perhaps an annual fast in remembrance of the fall, or at the end of the days of the week, the seventh day, which was the sabbath)
So although this would not count as conclusive proof (which our next example certainly does) it is clear that Adam and his family knew that God was to be worshiped, and it is clear from God's reaction to their offerings that acceptable worship involved blood sacrifice rather than grain offerings - something which they must have known from God. The words for the occasion when this took place, "at the end of days" are indicative of an appointed time for worship that took place after a certain number of days had passed, and this description does fit the idea of worshiping at the end of each week, on the seventh day. This view is strengthened by the fact that no other time frame for worship is mentioned in these early chapters of Genesis
What we are doing is to build the case for sabbath worship as a creation ordinance of God - something that is confirmed in the 10 Commandment but was not instituted in them. Most if not all of the Commandments were not new on Sinai but were simply codified in covenantal form there. We fully understand we must also show that the sabbath has moved to the first day of the week under the New Covenant. However, the creation ordinance argument needs to be made first to counter those who seem to believe that if the 4th Commandment dropped out of the moral law, so does any requirement to worship God one day in every seven. The fact is that even if that could happen (and it couldn't) the requirement would abide by means of creation ordinance.