One of the points he draws out is the parallel between the first day of creation when God createad the heavens and the earth and Sunday being the Lord's Day the day which is primarily an Easter celebration - we are a new creation - the New heavens and New earth.
This paragraph is very significant I think:
17. The connection between Sabbath rest and the theme of "remembering" God's wonders is found also in the Book of Deuteronomy (5:12-15), where the precept is grounded less in the work of creation than in the work of liberation accomplished by God in the Exodus: "You shall remember that you were a slave in the land of Egypt, and the Lord your God brought you out from there with mighty hand and outstretched arm; therefore the Lord your God commanded you to keep the Sabbath day" (Dt 5:15).
The command in the Law of Moses specifically gives the reason the hebrews were to keep the Sabbath - because of their deliverance. Another place says it is a special sign between God and the hebrew children.
Exodus 31:
16W herefore
the children of Israel shall keep the sabbath, to observe the sabbath throughout their generations,
for a perpetual covenant. 17I t
is a sign between me and the children of Israel for ever: for
in six days the LORD made heaven and earth, and on the seventh day he rested, and was refreshed.
18A nd he gave unto Moses, when he had made an end of communing with him upon mount Sinai, two tables of testimony, tables of stone, written with the finger of God.
With the new creation that is in Christ came a new liberation when He rose from the dead on Easter Morning, the first day of the week. This occured on the Lord's Day, Sunday. The Sabbath commandment was given specifical to the Israelites as a sign of the Old Covenant between them and God. Today, as a new creation in the New Covenant, following the apostolic tradition handed down from the Apostles themslves, we look to the Lord's Day for that day set apart for Him, our day of rest in the new creation.
And this is all just a small part in the beginning of his expounding on the Lord's Day.