Peter Leithart clears up some of the confusion about what the doctrine of sola Scriptura really means:
Now, I imagine that there are people who believe sola Scriptura as Smith describes it, and Protestants have always insisted that Scripture is a sufficient revelation of God’s will for us (cf., e.g., WCF 1.6). But neither the Reformers nor their heirs concluded that Scripture is the “sole” authority, nor did they deny the relative authority of human teachers. (If Calvin believed the Bible was the “sole” authority, why so much effort and time devoted to reading Augustine and Chrysostom?) As Smith himself points out, the Scriptures themselves point to human teachers and leaders who are to be honored as authorities. Smith is also correct that the New Testament writers encourage Christians to honor apostolic traditions. No argument there, but that’s because Smith has missed the point.
The argument is not about “sole” authority but “final” authority.
Once the actual issue is clarified, some of Smith’s rebuttals to Protestant defenses of sola Scriptura become shaky. He dismisses Matthew 15:1-6 as a text supporting sola Scriptura. Jesus, he says, was not “making a general point about . . . the epistemic illegitimacy of tradition per se.” Quite so, but quite irrelevant. The point is that the Pharisaical tradition (or some thread of that tradition) taught that it was legitimate for children to give money to God rather than caring for aging parents. Jesus refuted them by saying that their tradition nullifies Scripture. Scripture is Jesus’ trump card. He doesn’t point to alternative threads of Pharisaical tradition (though he doubtless could have). One might say, for Jesus Scripture has final authority to judge the legitimacy of tradition. One might say, sola Scriptura.
(Via: Justin Taylor)