The basic meaning of the English term "perfect" (and the Greek term which it translates) is "mature" or "complete." The entity to which reference is made -- "that which is perfect" -- is the completed Canon of Scripture.
At the time of the Incarnation, the Canon of Scripture was comprised solely of the portion of the English Bible today commonly (though erroneously) termed the "Old Testament". The Cannon was completed by the four so-called "Gospel Accounts", and by the epistles of Peter, John, and Paul.
The Book of Revelation did not complete the Canon. The Book of Revelation is a forgery crafted by the Talmudic Jew. Though there are other proofs, it is apparent simply from the standpoint of linguistic style that the author "John" cannot possibly have been the Apostle John. But setting aside questions of authorship, the spurious nature of the Book of Revelation can be seen clearly by the fact that the assertions found in the book contradict the teaching of the Scripture in general. Many generations of scholars, some of them devout Christians, have recognized that the Book of Revelation is a counterfeit, but, as Adam Clarke put it, the book is considered by most scholars too magnificent to relegate to the trash bin, though all recognize that it is a forgery.
The fledgling Church had temporary need of certain spiritual gifts, but that need ceased once the Canon was complete, whereupon the temporary gifts were done away. That the gift of prophecy, tongues, and knowledge were to be done away is plainly and indisputably declared by the Scripture, I Corinthians 13:8-10. In the King James Version, the English term "fail" translates a Greek word which means to exit the stage.
In addition to utilitarian temporary gifts such as prophecy, tongues, and knowledge, which were given to various Christians, certain miraculous gifts, in particular, healing, were bestowed upon the Apostles; this was to establish the authenticity of the claim of Apostolic authority. But once each of the Twelve (the twelfth being Paul, and not Matthias) was established as a genuine vicar of Christ Jesus, the need for exercise of miraculous gifts ceased. No better demonstration of that cessation is seen than in the inability of Paul to heal Epaphroditus (Philippians 2:25-30), Trophimius (II Timothy 4:20), and Timothy (I Timothy 5:23).