The aspects of worship, as we come together with the congregation of believers, are many and varied, and everyone has their own ideas and preferences. Some things happen for no other reason than "We've always done it that way". Other things are much more intentional, though sometimes the reasons are not always sound.
I believe it is well to always ask ourselves WHY? It's a simple question, but it can be applied to everything we do. Sometimes the answers have sound, theological reasons. Sometimes the answer is a valid, "Because we like it that way". Sometimes we include something only once-in-a-while because there is a solid reason for inclusion but other things are more urgent or useful.
Here are some of my thoughts about worship and my reasons that support them. I have stated some of my thoughts on music in other musings, so I will not dwell heavily on the subject of church music.
Prelude: I believe a musical prelude, during which the people sit quietly and prepare themselves for worship, is helpful. In our fast-paced society, we seldom have time to "Be still and know that I am God". We need this time to acclimate to the presence of God and His awesomeness.
Call to Worship: This says "Alright, you're here and ready... Let's get going!" It draws our attention from our personal preparation to corporate worship.
Invocation: This is our statement to God... "OK, I'm here. I know you're here too, and I want us to get together." This doesn't have to be an audible prayer every time we worship, but the sense of what must happen is important.
Songs of Praise & Worship: Music is a "Heart Language". When we worship with music, we express ourselves in a way that we cannot in any other way. The styles and types of music should be chosen to allow each and every person to participate in some way that is worshipful for them.
Confession: There are two types of confession. One is admission and repentance of sin. The other is affirmation of belief. Both are important, and while the public service is usually not the appropriate time for audible, detailed airing of our intimate shortcomings, the silent acknowledgement and repentance at this time is possibly the only time some will ever think about them. It is also good for us to state out loud what it is that we believe. It fixes our beliefs in our minds and provides a ready description to offer anyone who would wonder what we do believe. Without a good, short statement that we have often recited and understood, many of us are at loss if we're asked to state our faith.
The Law of God: While the keeping of the Ten Commandments is not necessary for salvation, they are God's statement of His expectations. Jesus' summary gives perspective and a mature understanding. These are words that should be recited often so that they are "... word(s) I have hid in my heart that I might not sin..." How can we expect people to know what God wants if they haven't heard the rules?
Pastoral / Congregational Prayer: God expects us to humble ourselves before Him. He wants us to bring our thanks, our needs and our hopes to Him. While some accuse a pastor of sermonizing during this prayer, it should include statements of the awesomeness, greatness and incomprehensibleness of God. It should include thanks. And it should include our requests. As part of corporate worship, in a large church, it could easily take more time that people are normally willing to spend, and so, will probably not be highly detailed.
Special music: This time has unfortunately, often become a time of performance, a time to show off our skills and reap the applause of the people. There is however, good reason to include special music in a worship service. One of God's blessings is opportunity. The special music spot is the opportunity for gifted people of the congregation to offer their particular talents to God and His people. This is also a time to use and encourage children and other budding talent in the congregation. If children do not learn to participate in worship with adults, they will not likely feel any need for it as they grow older. They quite literally won't know what they are missing.
Children's message: If there are children present and the societal demands allow time, a short period devoted to a simple, child-oriented message is often very good. An additional value is that sometimes, this is the only message that some adults will hear and understand. It is important that such a message is truly delivered on a level that is understandable for the children addressed and is doctrinally sound as well.
Scripture reading: For many people, this is the only scripture they will ever hear. The practice of using portions from both Old and New Testaments may be of value. Certainly, it is appropriate to read a sizable portion of scripture. If the text for the Message is in this reading, it will be more relevant for the listener. If the Scripture Reading is incorporated in the delivery of the message, that is acceptable, and without a doubt, the Message must be entirely compatible with scripture.
The Message: Part of worship is honoring God by learning what He wants us to know. The sermon is our effort to educate our people. It is a time to explain or teach what it is that we say we believe. It exposes people to the Word of God if they haven't read it themselves and it attempts to explain or expand our understanding of it. These are the lessons in life, the explanation of practical application of doctrine. In an aurally oriented society, many people learn best by hearing. This is that time to grow in knowledge of God and the history of man's relationship to Him. In the time allowed by societal expectations, there is little room for much social Gospel. The time is short to communicate all the lessons of Biblical importance to today's uneducated seekers.
The Lord's Supper: The celebration of Communion with God and His people is always appropriate but, in the interest of not allowing it to become too common-place, and because of the worldly time constraints that many apply to church services, many support the custom of this celebration every two or three months.
Benediction: As we leave the place and time set aside for corporate worship, it is reasonable that we exchange blessing between God and His people. The Aaronic blessing or those of the New Testament writers are appropriate and should be delivered by someone who is recognized as a mature mouthpiece of God. While the words may have the same meaning if delivered by a child, the impact of a statement by a mentor or exemplar is more meaningful to me.
The setting: Many people find meaning and comfort in symbols of worship. Stained glass windows, a centrally located cross (indicating the centrality of Jesus' sacrifice), a centrally located pulpit (indicating the centrality of the preaching of The Word), two pulpits with the more prominent one being used only for the delivery of the message (indicating that the Word of God is pre-eminent), calling the raised area in the front a platform rather than a stage (emphasizing a platform for preaching rather than a stage for performance), wearing robes, flags on or off the platform or no flags at all, an empty cross (indicating that Jesus' sacrifice was once, for all, and is finished), a crucifix (emphasizing Jesus' death); and more.
I am not one of those people. The reason I shy away from much symbolism is because symbols can be misinterpreted or controversial. (as in the empty cross versus the crucifix) I would prefer to see most symbols used in temporary applications (such as in banners) that are explained at their introduction and removed after a time.
Above all, I believe that corporate worship must be God-centered. Our purpose is to honor and communicate with the Almighty God. All other aspects of the corporate service must take second place to that. That said... within reason, if the answer to the question, "Why do this?" is a positive "it is useful to our communication with God" and "it is not a stumbling block to any of our number", then by all means, incorporate it into the public service.