The Ben. note on this passage suggests that the reference to Jeremiah is an argument supposed to be put forward by Eustathius, and immediately answered by Basil, but there seems no necessity of this.  Basil says nothing for or against the powers of the bishops who condemned Eustathius; he only points out the inconsistency of Eustathius in accepting their powers to ordain when it suited his purpose, while he refused to admit their authority to depose.  It is enough for Basil’s argument that Eustathius treated him as having authority.  On Basil’s own views as to the validity of heretical ordination, cf. Canon i., Letter clxxxviii.