Can you please point me to the area of teaching that shows the 613 laws are a Jewish myth? I would like to study this too.
The claim that there are 613 laws in the Old Testament first appeared in the third century A.D. when a Jewish Rabbi, named Simlai, mentioned it in a sermon that was recorded in Talmud Makkot 23b. The number became fixed in Jewish tradition, even though a large number of rabbis disagree with the number. It should be noted that Simlai did not provide a list of his 613 laws.
Probably the most notable proof that it is just a legend is the fact that there is no definitive list of the supposed 613 laws. To be sure, there are lists, but they vary. The list most commonly cited was not created until the twelfth century AD. A second problem is that the existing lists leave large sections of the Old Testament out, which one rabbi points out is not reasonable to think that there are no laws in those sections.
"This testimony is true. For this reason reprove them severely so that they may be sound in the faith, not paying attention to Jewish myths and commandments of men who turn away from the truth" (Titus 1:13-14).