That they should not enter (mē eiseleusesthai). Negative mē (cf. ei in Heb 3:11) and the future middle infinitive in indirect discourse.
To them that were disobedient (tois apeithēsasin). Dative masculine plural of the articular first aorist active participle of apeitheō, active disobedience with which compare apistias in Heb 3:12, Heb 3:19.