The Internal Testimony of The Spirit

What then is meant by this internal testimony of the Spirit? An internal testimony of the Spiritmay mean an extraordinary inspirtation or new direct revelation by which Christians are given special assurance that Scripture is God's Word, such as the assurance that was given to the prophets and apostles who received direct revelations from God. This assurance is independent either of the authority of the church or of any human arguments or reasonings. But this is not what we mean here by the internal testimony of the Spirit. Our faith in Scripture as God's Word is not based on any such private testimony given by the Holy Spirit. Nor is it based on any subjective feelings or experiences, for the following reasons:
1.Since the completion of Scripture, the church needs no new extraordinary direct revelations from God. This would overthrow the perfection of Scripture.
2.Those who are to believe will not be able, if new revelations are still being given, to protect themselves from delusions and from being imposed on by the deceits of Satan. New revelations are either to be tried by Scripture or they are exempt from such trial. If tried by Scripture, then these new revelations acknowledge Scripture to be a superior rule, judgment and testimony. So these new revelations cannot be that on which our faith can ultimately rest....
But that work of the Spirit which may be called an internal real testimony [of the Spirit] produces stability and assurance of faith.... From The Spirit and the Church by John Owen, abridged by R.J. K. Law