Some very profitable aspects of a godly assembly are related to form. It will be advantageous to review some of them.
The Lord's Supper Here is a form invested with power. No student of the Word of God would encourage informality in this ordinance. The bread, the fruit of the vine, and focused remembrance are all formal, not informal. We are not simply to let our memories wander about in otherwise noble things here. This is not the time to recall how we love our husbands, wives, or children. This is not the time to pray for our nation or seek the conversion of sinners. Our minds must be focused on the Lord Jesus Himself. That is the essence of valid formality--focus! Scripture admonishes us, "Seek those things which are above . . . Set your affection on things above, not on things on the earth" (Col. 3:1- 2). I suggest that it is exceedingly difficult to do this without distancing yourself from informality.
Think of the institution of this supper by our blessed Savior. He charged some of His disciples with making the environment "ready" (Mark 14:15; Luke 22:12). Recall how Jesus blessed and broke the bread, also giving thanks for the cup (Luke 24:30ff). He even stooped to wash the disciples feet, much to their consternation (John 13). After the supper, they also sung "a hymn" (Matt. 26:30).
Public Prayer
Prayer also falls into this category. An ordered approach to public prayer is encouraged. Prayers are to be focused on "all men," in distinction to purely selfish motives (1 Tim. 2:1). Those that hear the prayer are to be able to say "Amen at the giving of thanks" (1 Cor. 14:16). Prayer is itself a form--a container in which thought and contemplation are presented to God. When our blessed Lord taught us to pray, He provided a form for us. It was not a rigid form, but it was nevertheless a form, or outline (Matt. 6:9-13). He furnished areas on which we are to place emphasis. Never is such an approach more relevant than in the assembly.
Preaching
Preaching is attended with a degree of formality. Words are to be edifying (1 Cor. 14:26; Eph. 4:29), which requires discipline and focus. The Word itself is to be the substance of the presentation (2 Tim. 4:2). Things that generatequestions are to be avoided (1 Tim. 1:4). Informed and gifted hearers are to examine what is said (1 Cor. 14:29; 1 Cor. 10:15), finding if it is from God.
The point to be seen in all of this is that informality allows more into our assemblies than we want: things that are inhibiting and distracting. A good degree of honesty will confirm this to you.