It is necessary in Bible lessons to have an application. Without it the lesson has no practical benefit.
There are three kinds of Bible application. Ignoring any of them can lead to misunderstanding.
Historical Application
The Bible is accurate in all of its description of people, places, events, and words. It is truly inspired by God. Any question of the Bible’s inerrancy must be answered using a form of historical application. Apologists and students of prophecy place their application emphasis here, but any application of the Bible must believe the Bible to be factual or it will not be based in reality.
Bible belief as a true record of God’s inspired words engenders faith. Without this historical truth the Bible becomes an imaginative man-made storybook filled with anachronisms.
Overemphasizing the historical application can lead to a scientific approach to the Bible that appears irrelevant. The historical application is important in our study of every passage of the Bible.
Spiritual Application
It is in the Bible that we learn about God, his character, holiness, and any thing that has virtue. The spiritual application allows us to grow in godliness. Any question of what is good must be answered using a form of spiritual application. Many devotionals and moral literature use this application to communicate good manners.
This application teaches us what it is like to walk in the Spirit. Without this spiritual instruction believers revert to the works of the flesh, and live a carnal life without a zeal for good works. The Bible becomes a book of general morality and is not meaningful.
Overemphasizing the spiritual application can lead to a bland or false spirituality that ignores doctrine and compromises the truth for the sake of unity. A spiritual application is useful for our learning from all scripture.
Doctrinal Application
The Bible is where we discover the instructions for our direct involvement in God’s will. This type of doctrinal application is always subject to the context. Active participation in any instruction from God must first consider the doctrinal application. Doctrinal applications are not popular since they require right division, separation from false doctrines, and identification of errors. All scripture is profitable for doctrine, but not all doctrine is for our participation.
Without the doctrinal application the believer is confused about what God is telling them to do. Activities such as prayer, Bible study, holy days, and salvation become confusing. Right division encourages the doctrinal understanding of all of scripture and helps to eliminate the confusion.
It is hard to overemphasize this application since it is mostly absent from most Biblical application. When the doctrinal application ignores the historical or spiritual applications then it becomes a source of vain philosophy and religion.
Ignoring any of these kinds of Biblical application can make the Bible unprofitable and vanity at best and plain wrong at worst. All scripture is profitable, and using all three kinds of Biblical application makes it so.