It is interesting the viewpoints that various people can develop and espouse. Opinions are like weeds—free and flourishing (and oftentimes a nuisance). Sometimes, well-meaning brethren develop great misconceptions about roles and responsibilities within the church. I’ve heard many preachers tell the story of encountering the attitude of work needing to be done and met with the response in a meeting “Why doesn’t the preacher do it? Isn’t that what we hired him for?” But the work and roles and responsibilities in the church are not left up to subjective opinion; but rather, are dictated to us by the objective word of God.
“Why do we need deacons if we have a preacher and shepherds?”
Because work demands workers - Jesus said that “The harvest is plentiful but the workers are few.” (Matthew 9:36) - In other words, there is more work than there are workers. Work demands workers. There is more work to be done in the church than there are workers to do it. In just about every church, this is the case, and this church is no different. You may not be aware of all of the work that goes on or needs to be done, but just because you are not aware does not mean that it is not there. If anyone would ever like to volunteer for some of this work, the shepherds would be glad to help direct you in areas of growth in work and service in the church here. We will always have plenty of work... and always need more workers
Because we have a preacher and shepherds - Why does the church need a preacher? It’s not to unclog toilets, fix people’s cars, or organize potlucks. We need a preacher to preach. To fulfill the ministry of an evangelist (I & 2 Timothy & Titus). Why does the church need shepherds? Not to hold a title, or for status, or to sit on a board and make administrative decisions. We need shepherds to shepherd (Acts 20:28-31; I Peter 5:1-5). And because preachers and shepherds have a specific duty/work/ministry to fulfill, they need help in not being distracted from those duties. In Acts 6:1-6—the early church not only had preachers, but also likely shepherds and even had the Apostles!; yet when a ministry need arose; rather than the Apostles, or elders, or preachers being tasked with fulfilling that need instead the instruction was for the church to select servants (workers/deacons) to oversee this need to completion. The church needs deacons so that preachers and shepherds can focus more fully on their calling.
Because it’s God’s design/will - In Titus chapter one we see the design of the Lord’s church in having shepherds. Part of Titus’ work was in teaching the churches in Crete about selecting and having overseers. I Timothy three (written after Titus) addresses this same need, and the preachers role in teaching the church about selecting shepherds to serve, but also about selecting deacons to serve. This was not Timothy’s idea or design, it was not the apostle Paul’s idea or design, it was God’s design and God’s will. “...I am writing these things to you so that… you may know how one ought to behave in the household of God, which is the church of the living God, a pillar and support of the truth.” (1 Timothy 3:14-15) “All Scripture is breathed out by God and profitable for teaching, for reproof, for correction, and for training in righteousness, that the man of God may be complete, equipped for every good work.” (2 Timothy 3:16-17)
I’ve heard some people (in general, and some brethren in particular) question whether or not a church needs deacons, or even shepherds, or even a full-time preacher (evangelist) for that matter! Most often by people unable or unwilling to do (participate in) any of those works/duties in the kingdom themselves. And while the subjective opinions of man may vary greatly, I believe the objective word of God is clear. The church needs these servants. God teaches us so.