>> That is true if you believe that the institution that became the Roman Catholic church has faithfully carried out Christ's commission and is in fact the one and only true church. I happen to believe that the early church strayed from the truth when it came to God's holy days and that tradition has usurped biblical truth. <<
And when had Satan triumphed over Christ so totally that for 1800 years no Christian kept the Sabbath? The 1st-century church recognized Sunday as the Sabbath. Satan cannot triumph over the Churchm, as 7th-Day adventists unwittingly imply he has, for Christ told Peter as much.
Plenty of Christians kept the sabbath throughout history. Well into the 4th century it was apparently so prevelent that the early Roman church had to issue an edict at the council of Laodecia NOT to observe it by resting. Here is Canon XXIX from that council:
CANON XXIX.
CHRISTIANS must not judaize by resting on the Sabbath, but must work on that day, rather honouring the Lord's Day; and, if they can, resting then as Christians. But if any shall be found to be judaizers, let them be anathema from Christ.
The mere fact that they had to tell people not to observe the sabbath by "resting" over 300 years after the death of Christ shows that many many Christians must have been keeping it.