In the tenure of my life in the ministry I have grown accustomed to people being inaccurate in their understanding and articulation of the gospel, and biblical doctrines. Correcting people is the difficult part. The difficulty is not in identifying what's wrong, but the manner in which correction takes place.
So, is precision necessary and if so when?
The gospel is simple. I've sinned, Jesus died and rose again, salvation comes by faith in Christ alone. That is the gospel in a nutshell, and it is fairly simple. It is simple enough for a child to hear, understand and respond. It is not necessary for someone to be able to articulate justification, propitiation, substitutionary atonement and other key related doctrines in order to receive salvation. They don't need to be able to articulate them, but they do need to understand those concepts as part of a sound, evangelistic, gospel presentation.
But, that does not mean understanding those terms and being able to articulate them is not important. I think that it is a vital part of growing as a disciple to learn, and be taught, not only the meaning of those biblical truths, but also how to articulate them. That is where precision is necessary.
It is also necessary in evangelism. This is especially true in the Bible belt. Churched people, who are still lost, have been inoculated to an imprecise version of the gospel, that probably isn't the true gospel. It is disturbing to me to run across people who have a church background and when asked about their relationship with the Lord give a works based answer to describe it. That happens to me all the time! That is where I have to be precise in my evangelistic efforts. This does not mean that I use big words, but that I am precise with the concepts those big words contain.
How do you accomplish that precision and still communicate effectively? That takes effort and work. One of the best ways to hone your precision is to explain the gospel, precisely, to younger people. Practice explaining justification to your kids. They need to hear it, and you need to practice communicating it.
