I hear the sentiment often, and from many points of view, that it is not fitting for Messianic Jews to mourn and repent in the High Holiday season.
The argument goes something like this: Yeshua died to end the curse for our sins and give life. Since we have already obtained atonement, we should not join in with the Jewish community mourning, pleading, and repenting. Rather, for Messianic Jews, Yom Kippur should be a day for dancing and rejoicing in the atonement Yeshua made.
My quick response: this is not how the New Testament authors treat the issue at all. There is no New Testament verse which says,