It’s in the Bag: An Illustration of Sufficiency
Perhaps a picture will help solidify the previously discussed concept in our minds.
A set of golf clubs represents singularity-of-purpose and variety-of-function. A complete set includes upwards of fourteen clubs, all designed for the propulsion of a little white ball (i.e., singularity-of-purpose) but each in unique ways (i.e., variety-of-function). Some provide low and long trajectories, others high and short. Some are engineered and designed for use in sand traps, others for tee boxes, others for rough terrain, and still others for the fairway. There are clubs that will be used once or twice in a given round of golf while others will be used with much more regularity.
When a golfer steps onto any given course with a complete set of golf clubs, they are carrying with them all that they need to play the game—and play it well. Granted, their final score will depend on how effective they are at selecting and using the equipment they have at their disposal, but they are in need of nothing else. To add a hockey stick, leaf-blower, or tire iron to their golf bag would benefit them none—no matter how much they believe it will—and may even distract from using the proper tools at the proper times.
What’s the Point?
To bring this seemingly-abstract illustration to a hopefully useful point: What the complete set of golf clubs provides the golfer is sufficient for the purposes of the game they are about to play, for the telos for which they were designed. While proficiency with their use is another matter, a complete set of clubs provides all that is needed and all that is allowed for success in golf.
The Bible is like the Christians’ golf bag—a collection of books representing singularity-of-purpose and variety-of-function. The canon was given “that the man of God may be adequate, equipped for every good work”1 (i.e., singularity-of-purpose) and be progressively conformed to the image of Jesus Christ by the power of the Holy Spirit.2
However, the individual books and pericopes therein present unique thrusts (i.e., variety-of-function) that all contribute to that common telos. Some sections will be used more than others but, when used properly and at the appropriate moments and for the purposes for which they were designed, they are ideal for the task. The skill and proficiency with which a Christian uses Scripture will vary and can be improved with prayerful practice and dependant care, but the potential effectiveness of each section of the Bible is perfect for that which it was given. To add to, take away from, or mishandle its contents is to do ourselves—and the “game” we are playing, i.e., the command to “walk in a manner worthy of the calling with which [we] have been called”3—a massive disservice.
1 Rom 12:1–2; 2 Tim 3:17
2 Rom 8:29; 1 Cor 15:49; I understand that one could argue against the singularity of purpose for Scripture, perhaps suggesting divine self-disclosure (e.g., Pss 46:10; 119:10), the salvation of the lost (e.g., John 17:3; 20:30–31), or the mobilization of God’s people (e.g., Matt 2819–20) as possible scriptural foci. Ultimately, this should be considered a tangential issue to the one being addressed here. The question is, for whatever the purpose it was given, is the word of God sufficient in-and-of-itself to accomplish that purpose?
3 Eph 4:1