Joel Beeke on the limits of the sufficiency of Scripture:
The sufficiency of Scripture is, however, limited to the Bible’s purpose in revealing truth for our salvation, faith, and obedience (Ps. 19:7–11; John 20:31). The doctrine does not assert that the Bible is sufficient to guide all human activities in every respect, except in the most general way. The Bible does not claim to be a comprehensive encyclopedia of everything. Instead, it gives us “the words of the wise” so “that thy trust may be in the Lord” (Prov. 22:17, 19). The Holy Scriptures “are able to make thee wise unto salvation through faith which is in Christ Jesus” (2 Tim. 3:15). It is “profitable for doctrine, for reproof, for correction, for instruction in righteousness” (v. 16). Other matters must be governed by “the general rules of the Word, which are always to be observed,” such as “Whatsoever ye do, do all to the glory of God” (1 Cor. 10:31).