The Sufficiency of the Holy Scriptures

The Holy Scripture contains all things necessary to salvation. Whatever is not read therein, nor may be proved thereby, is not to be required of any person, that it should be believed as an article of faith, or be thought requisite or necessary to salvation. The 66 canonical books are listed.

Every Scripture is God-breathed and profitable for teaching, for reproof, for correction, and for instruction in righteousness, that each person who belongs to God may be complete, thoroughly equipped for every good work.
— 2 Timothy 3:16-17 (WEB)

Note

Sufficiency, not the sole authority. Wesley's broader epistemology placed Scripture as primary, supported by tradition, reason, and experience — the Wesleyan Quadrilateral.

Bible references

2 Timothy 3:15-17 · 2 Peter 1:20-21 · John 5:39 · Romans 15:4 · Acts 17:11 · Revelation 22:18-19