“Not that we are sufficient of ourselves to think any thing as of ourselves; but our sufficiency is of God; Who also hath made us able ministers of the new testament; not of the letter, but of the spirit: for the letter killeth, but the spirit giveth life.” (2 Corinthians 3:5-6 KJV)
Able ministers? As in qualified or competent ministers? How do you determine if a minister is qualified or competent? Okay, so that is a really big question. Depending on if you are asking a general opinion poll or an actual pastor search committee, you may get a very wide discrepancy in answers. Yet, has not God made us able ministers? It would then seem that the proof of our ministry abilities would be in our adherence to Him.
This brings up another delima. Is our adherence determined down to the letter or by the Spirit? An example... A person driving 40 miles per hour in a 35 miles per hour zone is considered to be speeding as per the letter of the law. The person actually driving may argue the speed limit ought to be 50 since the roads are good and there are no residential or school zones nearby and he is driving in the spirit of how traffic actually flows. I am not a traffic judge, but you get the gist of the difference. Our first inclination may be to reform the letters in the law such that it better matches the spirit in which things are actually done. In many ways this is very possible over time and with patience here on Earth. Yet, the letter of this law if adjusted only seems to be ratcheted up and not down. If a standard of how things ought to be done is acknowledged as a gold standard the only way to replace that standard is to do even better. Besides these letters seem to already be canonized into scripture and the obvious question is, would it be a good idea to change them even if we could? So, the real thing to notice about the letter is that it is introspective or self-examining rather than something that reaches out or grows. Not only is it introspective, but it is so infinitely self-examining that only an infinite being could possible comply with all the letters (see also Hebrews 10).
So, in what way does the spirit give life? You can use many visual descriptions like breathes life into, lifts up, or carries, but essentially the spirit enables you to be able because He is able. There is an enormous power in showing someone that they are genuinely capable. Capable of so many things under the direction of Jesus. Where the letter inevitably turns Man into machine, the Spirit breathes life into a new Man who can stand because of the healing hand of God. Under Jesus, things are now possible (see Luke 18:27). Real joy that goes deeper than happiness is now possible in part because you know things can, in due time, be accomplished. The sad part of the letter is that over time, it is easily misinterpreted to have a completely different meaning and is corrosive whereas the spirit or intent is easy reference and endures past all kinds of false accusations and malicious intents. The letter also defines the confines of the container. The spirit releases, radiates forth, bursts outward, and makes you want to share with and teach others. The spirit can actually exceed the minimums dictated by the standard and produce results that the letter at best can only regulate. If you think about it, even the will to perfect something is born of the passion in a person's spirit rather than a regulation which at best can only prod or goad. The letter may be good for measuring, but never creating. When God's Spirit enters you and sets you on the foundation of Christ, you begin to understand real meaning that is not necessarily opposed to the letter but how He fulfills every one of them. This understanding is what makes you an able minister of the new testament.
“Who art thou that judgest another man's servant? to his own master he standeth or falleth. Yea, he shall be holden up: for God is able to make him stand.” (Romans 14:4 KJV)