I can't explain it any better than John Henry Newman in his 1884 essay Inspiration in its Relation to Revelation "It is quite evident that this passage furnishes no argument whatever that the sacred Scripture, without Tradition, is the sole rule of faith; for, although sacred Scripture is 'profitable' for these four ends, still it is not said to be 'sufficient.' The Apostle [Paul] requires the aid of Tradition."
It also doesn't fit in with the meaning of 2 Thessalonians 2:15 "So then, brethren, stand fast, and hold the traditions which ye were taught, whether by word, or by epistle of ours"
It is true that without Scripture a man will not be "thoroughly equipped" --- the Scripture is necessary, but not sufficient. It is also true that without the apostolic preaching he will not be "thoroughly equipped," without the inspiration of thre Holy Spirit he will not be "thoroughly equipped," and without the interpretive authority of the Church, he will not be "fully equipped."
2 Peter 3: 15-16 Regard the patience of our Lord as salvation; even as our beloved brother Paul also, according to the wisdom given to him, wrote to you; as also in all of his letters, speaking in them of these things. In those, there are some things that are hard to understand, which the ignorant and unsettled twist, as they also do to the other Scriptures, to their own destruction.
Obviously you think that I need your interpretive authority; I don't seem to be "fully equipped" to understand these Scriptures on my own, do I? (You must agree that this is true!) If that is the case, why should I prefer your interpretive authority to that of the Church?
I never said you needed me to interpret anything. You are the one saying that one needs the Catholic church in order to correctly interpret Scripture. I disagree with that.