Protestant
Is Scripture alone (sola scriptura) a biblical teaching?
The Bible itself never claims to be the sole rule of faith; instead it commends apostolic Tradition and calls the Church, not a book alone, the 'pillar and foundation of truth.'
Catholic teaching
Sacred Scripture and Sacred Tradition together form one deposit of faith, entrusted to the Church and authentically interpreted by her Magisterium. Scripture arose from within the Church's living Tradition and cannot be rightly read apart from it.
Biblical foundation
Paul commands the Thessalonians to 'hold to the traditions... whether by word of mouth or by letter' (2 Thess 2:15), and calls the Church, not Scripture, 'the pillar and bulwark of the truth' (1 Tim 3:15); 2 Timothy 3:16 says Scripture is useful, not that it is the only rule.
Scripture references
Historical evidence
The very canon of Scripture was settled by Church councils in the fourth century relying on apostolic Tradition, showing that the Bible's own authority was recognized through the Church, not apart from her.
The Church Fathers
“What if the apostles had not in fact left writings to us? Would it not be necessary to follow the order of tradition?”