"WWJD" has become a phrase that is quite popular with churched people. So, have you ever considered just what Jesus DID do? Let's take just one point to examine: which did Jesus (our example of how to live pleasingly before God) keep as the Sabbath, Saturday or Sunday?

We submit to you that He kept Saturday, the 7th day Sabbath, in accordance with the instructions of the Torah (or "law" the first 5 books of the Old Testament, penned by Moses). In fact, there are at least 12 specific Scriptures detailing that He kept it and a total of 57 Scriptures mentioning the Saturday Sabbath in the gospels, alone.

If we are not to keep the Saturday Sabbath, then why is there no Scripture giving us permission to change it? We can't find any such Scripture, and even more to the point, there's no Scripture in the entire New Testament telling us that Jesus (Y'shua) or His disciples ever changed their practice of keeping the Saturday Sabbath.

Historically, the catholic church changed the Sabbath from Saturday to Sunday because that was the day Jesus supposedly arose (which is incorrect, see The Two Sabbaths of Passover). However, that point aside, the question remains as to whether man has the authority to arbitrarily change specific instructions given by God, in this case keeping the 7th day Sabbath set apart ["holy"]), or whether God's instructions, which Jesus and His disciples kept and never changed, are still in effect, today.

Even though there is a deeper meaning, Hebrews seems to refer to there being a specific 
Sabbath:

     4. For He has said somewhere concerning the seventh day: "AND GOD RESTED ON
     THE SEVENTH DAY FROM ALL HIS WORKS";
     5 and again in this passage, "THEY SHALL NOT ENTER MY REST." 
     6 Therefore, since it remains for some to enter it, and those who formerly had good news
     preached to them failed to enter because of disobedience,
     7 He again fixes a certain day, "Today," saying through David after so long a time just as
     has been said before,

                        "TODAY IF YOU HEAR HIS VOICE,
                        DO NOT HARDEN YOUR HEARTS."

     8 For if Joshua had given them rest, He would not have spoken of another day after that.
     9 So there remains a Sabbath rest for the people of God.
     10 For the one who has entered His rest has himself also rested from his works, as God did 
     from His.
     11 Therefore let us be diligent to enter that rest, so that no one will fall, through   
     following the same example of disobedience.  Heb 4:4-11