The words of the Bible are the words of God the Holy Spirit — they are not merely words about God or dead words that the Holy Spirit must unlock for us, no they are the true God-breathed words that our Lord has graciously given us —, and wherever those words are carefully and prayerfully taught, studied, and meditated on, that is good and sufficient. As it's written: "All Scripture is breathed out by God and profitable for teaching, for reproof, for correction, and for training in righteousness, that the man of God may be competent, equipped for every good work."
So on the one hand, a degree is not the same as ordination, and on the other, we don't have to climb some mountaintop for secret wisdom. God's Word is given to His whole Church in full, and to be firmly rooted in His Word is to be spiritual, properly speaking. His Word is a lamp to our feet and a light to our path.
That said, the Bible does lay out very clearly that those who aspire to the pastoral office should train with the church. See the epistles to Timothy, for example.