Let us not be (mē ginōmetha). Present middle subjunctive (volitive), “Let us cease becoming vainglorious” (kenodoxoi), late word only here in N.T. (kenos, doxa). Once in Epictetus in same sense.
Provoking one another (allēlous prokaloumenoi). Old word prokaleō, to call forth, to challenge to combat. Only here in N.T. and in bad sense. The word for “provoke” in Heb 10:24 is paroxusmon (our “paroxysm”).
Envying (phthonountes). Old verb from phthonos. Only here in N.T.