The Church teaches that interpretation of the Bible must be done
within “the living Tradition of the whole Church”. According to a saying of the Fathers, Sacred Scripture is written principally in the Church’s heart rather than in documents and records, for the Church carries in her Tradition the living memorial of God’s Word, and it is the Holy Spirit who gives her the spiritual interpretation of the Scripture (“. . . according to the spiritual meaning which the Spirit grants to the Church”). [Catechism of the Catholic Church, §113].
In short, the true and correct interpretation of Scripture conforms to that which the Church has always taught. This means that the exegete is not a solitary agent who may work without reference or appeal to Sacred Tradition; rather, his work is informed and guided by the Holy Spirit through the teaching of the Church.
St. Thomas Aquinas has some helpful things to say concerning prophecy which I think shed light on this subject. He reminds us of the very purpose of prophecy (and by extension the purpose of divine revelation as a whole): “the end of prophecy is the manifestation of a truth that surpasses the faculty of man” (Summa Theologiæ II-II q.174 a.2). Why did God give us revelation? What is Scripture’s purpose? To convey truth that man could not reach on his own. That is why, as Thomas says a little earlier, “not every prophet knows what he prophesies” (ibid., II-II q.173 a.4).
Nevertheless it must be observed that since the prophet’s mind is a defective instrument, as stated above, even true prophets know not all that the Holy Ghost means by the things they see, or speak, or even do. (ibid.)
No man’s knowledge is perfect, and this is particularly true when it comes to those supernatural things which by definition exceed human capacity entirely. Aquinas says that one effect of human weakness when it comes to service as authors of Scripture is that the authors “know not all that the Holy Ghost means.” A consequence of this is that an interpretation of the Bible which focuses solely upon the meaning that the human authors intended to convey is defective, precisely because what God means by the words of the Bible is (at least some of the time) beyond what the human authors could have possibly meant themselves.
What then? Well, then we need to resort to the Church, the pillar and foundation of truth (1 Timothy 3:15), as our help and guide when it comes to understanding the Bible.