Ephesians 5:17 ÔÇ£Wherefore be ye not unwise, but understanding what the will of the Lord is.ÔÇØ
In this passage, Paul exhorts the Ephesian brethren to be not unwise, but instead, to be wise. True wisdom is the knowledge and understanding of the will of God and the application thereof. The will of God is found in His word. It is only through the Word of God that we have any knowledge of Him. Without this revealed knowledge of God, there is would be no true wisdom.
Paul exhorts them to understand the will of God. To do this, one must study the Word of God. 2 Timothy 2:15 commands us to study the Word of God to show ourselves approved of God so that we may rightly divide the truth. John 17:7 teaches us that the Word of God is truth. Yes, truth does exist. It exists in the divine precepts of the Word of God.
We can know the truth ÔÇô Jesus said so. John 8:31-32 says, ÔÇ£Then said Jesus to those Jews which believed on him, If ye continue in my word, then are ye my disciples indeed; and ye shall know the truth, and the truth shall make you free.ÔÇØ Jesus teaches here that we can know the truth by continuing in His word.
The Bible can be understood by all men. The Calvinistic doctrine on the fallen state of man says that, since the fall, man is no longer in a state where he is able to understand the will of God. They teach that man can only come to an understanding of the Word of God through a direct operation of the Holy Spirit. Yet, the Bible refutes this doctrine. Paul, in 2 Timothy 3:15, teaches that Timothy had known the Holy Scripture from a child. He had, from his childhood understood the Bible. He did not come to that understanding of the Old Testament scriptures by a direct operation of the Holy Spirit, but by the instruction he received in the word from his mother and his grandmother. (2 Timothy 1:5)
We can know the truth through a diligent study of the Word of God. All mankind can know the truth and understand it alike. For we know, according to 2 Peter 1:20, that the scriptures are not of any private interpretation, but that they are of, or by the inspiration of the Holy Spirit. All men can have the same understanding of the Word of God that Paul had. In Ephesians 3:4, he tells us that we can understand his knowledge when we read his inspired words.
Finally, we must all be able to understand the Bible alike because it is the only standard that will judge us in the last day (John 12:48-50).