The One And Only
You've probably been in a position to attend or at least hear the phrase non-denominational service. My experience has been that these are usually inter-denominational because they usually contain elements from several denominations and doctrines and typically boast the acceptance of any faith owned by the attendees. But that's not "non"-denominational at all. There are still differences of beliefs, and divisions concerning matters of faith, even if you chose to hold those back for a worship period.
Paul says this, "I appeal to you, brothers and sisters, in the name of our Lord Jesus Christ, that all of you agree with one another in what you say and that there be no divisions among you, but that you be perfectly united in mind and thought.? (1 Cor 1:10) "...watch out for those who cause divisions and put obstacles in your way that are contrary to the teaching you have learned. Keep away from them." (Rom 16:17)
In the latter portion of the 1700's and into the early to mid 1800's, several religious groups were 'reforming' their ways, as they moved to get away from what they had determined was religious error, some grievous. There was likewise a movement trying to 'restore' (not reform) religious practices to those authorized specifically in the New Testament and to be the church of the New Testament with nothing added and nothing lacking. That remains the goal today of the churches of Christ, although some groups have chosen to "modernize" and have drifted back into muddy waters.
Christ only intended for there to be ONE church, THE church. The hundreds if not thousands of different groups with differing beliefs that we see today is not the Bible plan, and to have to even say non-denominational means man strayed from the divine intention. We should not have to say "non-denominational Christianity". We should be able to leave the "non" off and say Christianity takes on the Bible pattern, with Christ as the builder and chief cornerstone. He is the head, and it is His authority in all matters. No room for man's thinking (Prov 14:12, 16:25).
God says don't add or take away from His all-sufficient guide to Christianity, and that includes the worship period (Rev 22:18-19, Gal 1:8, Jn 9). He has thoroughly furnished us with everything we need for our doctrine, reproof, correction and instruction in righteousness (2 Tim 3:16-17). True (New Testament) Christians accept the scriptures, obey the Gospel, and pattern their lives after the divinely taught principles, and there is no need to interject man-made thinking into our teaching, believing or worshiping.
According to scripture, Christians are Christians ONLY, having been added to the church that belongs to Christ following obedience to His commands of hearing the Good News (Mark 16:15, Rom 10:17, believing that message and believing the deity of our Lord (Acts 16:31, 10:43) repenting of the sin in our lives (Luke 13:3, Acts 17:30) confessing Him as Lord (Rom 10:9, 32) and being baptized into Jesus to be saved and have our sins removed (Acts 2:38, Mark 16:16, 1 Peter 3:21-22). Then we are placed into His church by Christ Himself (Acts 2:47).
We are in the church of the New Testament, established by Jesus (Matt 16:18), and we accept no other creed but His (Rom 1:16). We strive to live Godly lives, knowing that we can't do so perfectly, and we receive continual cleansing of our sins by His blood (1 John 1:7-9). Our devotion and affection belong to Him and heavenly things (Col 3:12) and we put away earthly things (Col 3:5-10 and others).
Many verses regulate worship practices and divine principles in living and doctrine. Here are just a few for you to reference: Mt 16:18, 1 Cor 3:11, Eph 1:22-23, Heb 1:1-3, Col 3:17, Eph 5:19, 1 Thess 5:17-18, Acts 2:38, Acts 2:42, Acts 20:7, 1 Cor 16:1-2, Phil 1:1, Acts 20:28, Acts 14:23, 1 Pet 5:1-3, 2 Tim 4:2-3).
Today, do you find yourself meeting the New Testament guide to Christianity, or have you possibly been influenced by man-made teachings that are not a part of Christ's teachings. The first places you in His church, the church of the New Testament, Christ's church that He established. Following man-made teachings would, by the very definition, cause us to be part of a denomination, something that has split away from the genuine original, and would likewise have us being part of something that Jesus rejects, because we are a "division", and are no longer "perfectly united in mind and thought". (1 Cor 1:10)
Christ made it simple and easy to be part of His church. He made our worship process simple. It was never intended to be a production. He gave us simple easy to follow instructions for life and Godliness. Consider today these things, pray fervently about them, and see if there is a need to restore anything to it's proper place.