So that you may  prove what the will of God is

Now we come to the purpose clause, in other words this tells us why we are to do the previous things. The purpose is to prove, what is being proven is the will of God and the will of God is good, acceptable and perfect.
The word translated as prove is δοκιμάζειν. In order to understand it we will need to look at a few other verses where it is used. I had to look through several lexicons before I settled upon the one with the best definition and that is from Louw and Nida.
LN 27.45 δοκιμάζωa; δοκιμήa, ῆς f; δοκίμιονa, ου n; δοκιμασία, ας f: to try to learn the genuineness of something by examination and testing, often through actual use—‘to test, to examine, to try to determine the genuineness of, testing.’[1]
The first verse that we need to look at is Luke 12:56. It occurs twice in this verse and in the NASB is translated analyze and in the HCSB as interpret. The main point of the verse is that they can see the evidence and come to a rational conclusion (the first part of the verse) or they can see the evidence and come to an irrational conclusion (The last part of the verse). In both cases it involves a consideration of facts to reach a conclusion.
The next verse we shall consider is Romans 1:28. Here the NASB translates it at see fit and the HCSB as think it worthwhile. Once again we have a consideration of evidence, the rejection of a rational conclusion and here I want to notice the consequence. God gave them over to a depraved mind (NASB) worthless mind (HCSB). The word used is ἀδόκιμον; this is a negation of δοκιμάζω in the adjective form. In other words God removes their ability to reach a rational conclusion. I have experienced this myself while I was under discipline. And in my case it not only involved the inability to reach a rational conclusion in certain areas it included the inability to understand why others could not reach the same conclusions that I did. Only now after being restored to God can I see how irrational that I was.
So the idea that we have being expressed here is consider the evidence and reach a rational conclusion about the will of God. Based upon the evidence the conclusion that one will reach is that it is that the will of God is good acceptable and perfect (NASB), good, pleasing and perfect (HCSB). It is not my intention to go into a full study of the will of God right now, but I do want to say that when someone begins seeking God’s will they will find that it is good, pleasing and perfect. It is also something that must be pursued starting with the things that are revealed in God’s word before He will begin to reveal specific things to that person.

Summation:
I hope that verse one and two have impressed upon you that everything begins with a right relationship with God. It involves orienting yourself to God and His plan and adjusting yourself accordingly. Do not expect God to adjust to you; once you stop trying to adjust God to your way of thinking then and only then can God begin to adjust your self concept. As God makes this adjustment He will do so slowly and in His time and in such a way as to bring the maximum glory to Christ.

[1]Louw, J. P., & Nida, E. A. (1996, c1989). Greek-English lexicon of the New Testament : Based on semantic domains (electronic ed. of the 2nd edition.) (1:331). New York: United Bible societies.