I have a question about the Messianic Jewish movement. I searched on both of your sites and couldn't find if you wrote on this topic.

My sister who isn't part of the church is pretty religious with her husband and recently started worshiping as a Messianic Jew. I learned about it this month when I invited her to the beach Saturday and she said she couldn't because she was "Celebrating" Shabbat.  I found it odd and asked her why she decided to move to that faith; her response was in order to stay closer to the Hebraic roots of our faith, the faith that Yeshua lived and thought. This is the second time I've run into this as one of our disciple brothers left to that movement six years ago. I really don't know what to think about it. I would love to see if you can shed any light on this topic. It seems as if they are saying that we as Christians are not worshiping fully as was intended. Thank you very much.

My thoughts on this are all found in these three podcasts:
Moseley (book review)
The Sabbath

You might also contact our evangelist/teacher Arturo in Mexico City, as a couple of years back this was a huge issue.

Sorry I can't engage more at this time, but these podcasts were recorded with your exact questions in mind.