Well that would be true if it were solely hermeneutics that were going into this. Remember, we don't hold to Sola Scriptura! :)
Look, we simply do not approach Scripture as if we were a purely blank cultural/historical slate, and as if the Holy Spirit would somehow be our infallible guide to reconstructing Christian worship based on what we find in the NT (or what we think we find).
For us the faith began as a community not as a book, with traditions passed down from the Apostles to each subsequent generation in various places and among various cultures. The book, i.e. the NT, is an infallible guide to Christianity, but it is not a complete guide to Christianity....as evidenced in the fact that the Trinity does not explicitly appear in it.
If you ask me, can I prove the Catholic priesthood from that text, of course the answer is no. I can't prove that anymore than you can prove Wednesday Night Bible Studies. But understanding that the priesthood was already there from Peter/James/John through Clement through Irenaeus all the way up to the present...then we can look at texts like that and see a clear relationship.
PLEASE clarify that. Jesus spoke by his own mouth saying that the Holy Spirit would guide us into all Truth. You can't be implying that He's not infallible. You cannot possibly be opining that He needs help in giving that guidance. At least, you cannot be doing either of those things without being heretical, which I doubt is the case. So, more clarification of your precise meaning is needed.
Regarding the priesthood, I recommend a thorough reading of the New Testament book of Hebrews; especially chs 5-10 where the import and implications of Jesus' designation as High Priest in the Order of Melchizedek are laid out.
The writer of Hebrews, lays out the orthodox Christian explanation of who Jesus is, and what he accomplished, in a way that would be immediately understood by members of the Judaic culture, which is to be expected because Jesus life and work fulfilled and retired the requirements of the Old Covenant, replacing by his perfect sacrifice that way of imperfect sacrifices, and opening for us by his own flesh upon the cross, a new and living way, sanctified in His own blood.
As the writer says, "having boldness to enter into the holiest place by the blood of Jesus...let us draw near."
In the context, this drawing near is as the Old Testament High Priest alone could once, annually, draw near to the Ark of The Covenant, to appear before The LORD Who sat enthroned between the two cherubim on the atonement cover and offer the required sacrifices in dry-mouthed sobriety, and with trembling.
In teh same way, now, owing to Christ's position as High Priest in the Order of Melchizedek we may also draw near, but with boldness.
And THIS is the wonder of the gospel; that all the world of sinful man has been granted free and open access to that Holiest Place by God's gracious sacrifice of the Only Sufficient Mediator.