We must have conviction. To represent the Lord, be sure you have conviction. How do you get conviction? Make sure you understand the message you believe. Make sure you understand the doctrines. Make sure you understand the biblical explanation for everything you believe in, so that it is firmly in your heart. We have even known people who, one moment, were great preachers, and so many years later had abandoned many of the things they used to assert in their preaching. It has been said of them, they might have had opinions, but they didn't have convictions. There have sometimes been preachers who expressed the views and the doctrines and the language which they were brought up with and they were taught. But as the years go by it is made clear that they are not actually convicted about them, and convinced by them, and they abandon and lose them. That is a tragedy. If the Lord delays his coming, how many of us in ten or twenty years-time will be as firm on the things we believe, or it will be revealed that we never deeply believe those things? I have known people who were very fervent when they were in their early twenties. Now they still go to church, but they are all very blasé and relaxed about things. ‘Oh, these things don't matter so much – this and that: opposite views; it doesn’t matter. I don't take it seriously. That is a mark of immaturity. I used to take these things awfully seriously, when I was younger.’ And people reveal they didn't really have convictions; they didn't see the importance of it, and the truth of God. Well, Jeremiah was given deep conviction. The Lord touched his mouth. It was almost as though – he says it later – he ate the word of God, ingested it, and it went right down within him. Do make sure you have convictions, study the doctrines, deepen in the faith. Don't just stay only with the doctrines of salvation, as some sadly do. That is a great shame. There are many additional things we have to learn.
It is the same with us. As a Christian your mouth is the Lord's. You are never off duty. You are never out of commission. If you are at home and the children are being unusually irritating (and it can happen), perhaps even deliberately irritating, you are on duty for the Lord. You cannot lose your composure or your dependence upon him. Or in the place of business, something really callous and unfair has happened, but you are on duty for the Lord – you cannot react in a fleshly way. Of course, it is the same when we represent the Lord. If you teach or if you preach you are always now on duty. He has touched your mouth. Never are you going to take a holiday in the world, or do something completely wrong that you wouldn’t want to tell anybody about. You are always available for him and speaking his word.
‘And the LORD said unto me, Behold, I have put my words in thy mouth.’ That word ‘my’ is emphatic. We need to get this across even to some preachers. All some do is tell stories, even Bible believing preachers. They make up joke-stories and use them as the basis of witness. Well of course, you can illustrate; that is good. You can use things that serve as very good analogies for Christian truth to help understanding. But to substitute stories for the explaining and presenting of God's Word; to put that on one side, that is scandalous.