Why is it important to rely solely on Scripture for doctrine?

Relying solely on Scripture as the foundation for doctrine is crucial because the Bible is the only infallible source of truth. As stated in 2 Timothy 3:16-17, all Scripture is inspired by God and profitable for teaching, reproof, correction, and training in righteousness. When doctrines are built upon human traditions or experiences, as warned against in Matthew 15, they can lead to confusion and deviation from the gospel. Thus, believers are called to examine all teachings against Scripture to maintain the purity and accuracy of their faith.