It is the duty of ministers of the Gospel to expose the Scriptures. They must do that in the assurance that the Scriptures are the infallible and inerrant Word of God for all ages. The application is a part of the exposition. When we think that the application is not immediately related to the exposition, we in fact see the Bible just as an historical document. In that case the sources for the application of the biblical message come from outside the Bible. Knowledge of grammar, biblical history and languages is highly useful. We must compare Scripture with Scripture. We must reject however exegetical methods, which are not based on the self-witness of the Bible.
Our approach to the Bible is never neutral. We must approach the Bible in the awareness that it is the voice of the living of God. Not our reason must judge the Bible, but the Bible must judge our reason. What we need above all is the enlightening of the Holy Spirit. Otherwise our knowledge of the Bible and of biblical exegesis can be very great, but it is just an encyclopaedic knowledge. For that reason exposing the Scripture, we miss the real point. How we have to pray daily: "Open thou mine eyes, that I may behold wondrous things out of thy law (Psalms 119:18)"
The end of the authority of Scripture
God has given us his Word to make us wise unto salvation. Defending the infallibility of Scripture must never become an aim in itself. Our aim must be that we and other people glorify the triune God who has revealed himself to us and speaks to us in his Word. When we have our reservations about the divine origin of the Scripture and its divine inspiration, we cannot speak with authority any longer.
Prophets and apostles knew themselves to be spokesmen of the living God. They said: "Thus saith the LORD". Accepting the books of prophets and apostles as the Word of God, ministers of the gospel preaching the Word may speak and must speak which the same assurance: "Now then we are ambassadors for Christ, as though God did beseech you by us: we pray you in Christ's stead, be ye reconciled to God. (2 Corinthians 5:20)"