There are several answers to this question; but we would remark, before proceeding to give any answer, that the church is in possession, has from the moment of the descent of the Holy Ghost upon the apostles on the day of Pentecost claimed to be in possession of the authority in question, and has had her claim acknowledged by the whole body of the faithful, and denied by none except those who deny or impugn authority itself. Being in possession, it is for those who question her right to show that she is wrongfully in possession. They are, to use a legal term, the plaintiffs in action, and must make out their case. Every one is presumed in law to be innocent till proven guilty. The church must be presumed to be rightfully in possession till the contrary is shown. They who question her possession must, then, adduce at least _prima facie_ evidence for ousting her before she can be called upon to produce her title-deeds. This has never been done, and never can be done; for, if it could be done, some of our able and learned Protestant divines would, in the course of the last three hundred years and over, have done it. There is, then, in reality no need, in order to justify the faith of Catholics, to prove by extrinsic testimony the divine institution and commission of the church to teach all men and nations all things whatsoever God has revealed and commanded to be believed. But we have no disposition to avail ourselves just now of what some may regard as a mere legal technicality. We answer the question by saying the church is herself the witness in the case, and accredits herself, or her existence itself proves her divine institution, commission, and assistance or guidance.