The primary Catholic argument against
sola scriptura is that the Bible does not explicitly teach
sola scriptura. Catholics argue that the Bible nowhere states that it is the only authoritative guide for faith and practice. However, this is only true in the shallowest sense. The principle is strongly indicated by verses such as
Acts 17:11, which commends the Bereans for testing doctrine—taught by an apostle, no less—to the written Word.
Sola scriptura is all-but-explicitly indicated in
1 Corinthians 4:6, where Paul warns not to “go beyond what is written.” Jesus Himself criticized those who allowed traditions to override the explicit commands of God in
Mark 7:6–9.
Whether
sola scriptura is overtly mentioned in the Bible or not, Catholicism fails to recognize a crucially important issue. We know that the Bible is the Word of God. The Bible declares itself to be God-breathed, inerrant, and authoritative. We also know that God does not change His mind or contradict Himself. So, while the Bible itself may not explicitly argue for
sola scriptura, it most definitely does not allow for traditions that contradict its message.
Sola scriptura is not as much of an argument against tradition as it is an argument against unbiblical, extra-biblical and/or anti-biblical doctrines. The only way to know for sure what God expects of us is to stay true to what we know He has revealed—the Bible. We can know, beyond the shadow of any doubt, that Scripture is true, authoritative, and reliable. The same cannot be said of tradition.