"Yeah, when you go to Temple on the Sabbath, eat Kosher, don't mix fabrics, celebrate Passover (which Jesus himself said to keep as it would mark his second coming), etc, you let me know."
I don't keep Sabbath, etc. Because I'm not Jewish. The Mosaic law was a contract been God and Israel only. Even so, Christ completely fulfilled the law, and his righteousness was "imputed" (placed into my account) by faith.
As a Christian I operate under the "Law of Christ". Found in the New Testament. The laws are very similar, since the both come from the same law giver. The moral standards regarding marriage and sex outside of marriage have not changed over time. (I Corinthians 6: 9-10) Those who come to Christ are changed from the inside out. "and such WERE some of you." (I Corinthians 6:11)
"No, because none of that is in the Old Testament."
Yeshua, Jesus is the Jewish Messiah. The fulfillment of about 100 O.T. prophesies. Jesus is Jehovah of the O.T. who took on a human body and was born in a manger. He came for the purpose of dying for our sins on the Cross. He then rose from the dead.
God paid the penalty for MY sins HIMSELF! What love!