The title is an understandable question, especially in light of the religious division and confusion that exists in Christendom today. Of the counted minimum of two thousand different sects and faiths which proclaim to be Christian, all have great regard for the Bible and claim to follow it. However, common sense suggests that such is not the case when all proclaim to follow the Bible and yet believe and practice different ideas and doctrines.
Jesus knew that we could understand his Word in the same way and follow it with complete unity (John 17:20-23). So did Paul (Phil. 2:2). After Christianity started on the day of Pentecost after Christ’s death, the first converts “continued steadfastly in the apostles’ teaching” (Acts 2:42) and “the multitude of them that believed were of one heart and soul” (Acts 4:32). Quite a contrast from today! The saints in Rome were instructed to be on the lookout for those who caused “divisions and offenses contrary to the doctrine” they had learned, and avoid them (Rom. 16:17) How could they have obeyed that command without being taught to agree upon the doctrine that they had been taught? When a congregation was divided, Paul by divine inspiration wrote them that there should be no divisions among them and commanded them to speak the same thing (1 Cor. 1:10). How could this divine order be carried out if people are unable to understand the Word of God alike?
The reasons there are divisions about what the Bible says are many. First, all of us and our judgments are not perfect. Either by failing to study diligently or by failing to practice proper, consistent interpretive principles, we misunderstand biblical teaching and divide over it. Secondly, some believe that the Holy Spirit directs us in our study of Scripture and leads us to the truth, but such an idea is proven incorrect time and time again when two men both claim that the Spirit guided them to different conclusions about the same biblical passage. Thirdly, efforts to accurately interpret the Bible are often hindered by an absence of complete, 100% open-minded objectivity. Some subconsciously try to avoid dealing with the guilt of their sin and so twist the Scriptures to suit their ungodly lifestyles, while others are too loyal to family, peers, or their own religion and habits and thus approach the Bible with a closed mind.
When someone says that we can’t understand God’s will alike, that person has either never really engaged in a diligent, systematic study of the Bible or he is somehow seeking to justify a religious view or practice that is not according to the Bible. Therefore he attacks the Bible as being a book that no one can understand rather than admitting that he believes something that God does not teach. However, we all can understand Scripture alike.
We just choose not to.