I would be the first to agree that everyone has a right and permission to act out their spirituality any way they want to. But, having said that, I will also say that most acts of spirituality does not impress God and turns off many human beings. Jesus spoke of the Pharisees as the Bible described them. Even though they were correct regarding the resurrection of the dead, they were a constant target of Christ, showing how they were pretenders and were a great detriment to the kingdom of God.
By now you may think you know where I am going with this article, but read on.
The scripture admonishes us to be Holy as He (God) is holy. Any student of the Bible knows that the great mystery of the New Testament Christian is, "Christ in you."
There are three new testament verses where the word spiritual is used as a description of a Christian. 1 Cor. 2:15; 14:37 & Gal 6:1. These three references give a particular picture of what it means to be a spiritual Christian, one also shows that not all Christians are spiritual. These three verses combined with 2 Cor. 2:14 advises any Christian to desire to be spiritual. So it becomes necessary to figure out how to become and maintain spirituality.
Obviously, one must be born of the Spirit and indwelt by the Holy Spirit to be spiritual. One must be a student and adept at knowing scripture having in mind the Biblical spiritual characters and how they behaved.
The utmost spiritual example would be Jesus Christ, Himself. It is a wonderful study to just follow Christ as He walked among men. He was able to apply the scriptures to those He met including the devil himself. He was able to fulfill (walk according) to what scripture enjoined Him to be. He was kind yet honest in all His encounters. He was able to present the grace and the judgment of God, simultaneously.
Paul, the Apostle, would certainly come next as an example of a spiritual man. Romans chapter 7 confesses his humanity in conflict with his spiritual self. Again he was a walking fountain of scripture and its applications. His insight was proven in his interpretation of Old Testament Scripture in light of Christ. Much of his writings revealed the intent of God and the future of the kingdom of Christ.
Following Paul, we should observe Peter & John with their descriptions and testimonies of their actual lives in Christ. Many of the Old Testament characters were also examples of spiritual people. They took their tasks as God's messengers and envoys very seriously. Perhaps their spirituality could be measured by the reaction of their subjects to their ministry.
One thing for sure, there is no evidence that any one who tried to show spirituality or act spiritual outside scripture was ever accepted as spiritual.
Many preachers, priests and titled clerics want to appear spiritual, and haven't a clue as to their fake presentations. They only do damage to the testimony of Christ and the meaning of the Gospel.
On the other side of that picture, are those individuals who feel it hypocritical to be spiritual so they want to appear as one of the good ol' boys and are never an example of Godliness.
A spiritual person is one who is totally committed to the service of God knowing and believing that he or she are on a mission from God to be the light of Jesus Christ to any and all that they come in contact with. Comprehending the Bible and apt to teach the whole counsel of God.
Of course a spiritual person must have a genuine relationship with the Lord Himself which is evident in his prayer and knowledge of the Word of God.