The Epistle to the Hebrews, the authorship of which has been long debated, urges the Hebrew Christian community not to fall back into Judaism.

Hebrews 7

7:11 If therefore perfection were by the Levitical priesthood, (for under it the people received the law,) what further need was there that another priest should rise after the order of Melchisedec, and not be called after the order of Aaron?