The word translated fervent' is literally boiling. The metaphor is very plain and intelligible. The spirit brought into contact with Christian truth and with the fire of the Holy Spirit will naturally have its temperature raised, and will be moved by the warm touch as heat makes water in a pot hung above a fire boil. Such emotion, produced by the touch of the fiery Spirit of God, is what Paul desires for, and enjoins on, all Christians; for such emotion is the only way by which the diligence, without which no Christian progress will be made, can be kept up.
No man will work long at a task that his heart is not in; or if he does, because he is obliged, the work will be slavery. In order, then, that diligence may neither languish and become slothfulness, nor be felt to be a heavy weight and an unwelcome necessity, Paul here bids us see to it that our hearts are moved because there is a fire below which makes the soul's depths boil in earnest.'
Now, of course, I know that, as a great teacher has told us, The gods approve the depth and not the tumult of the soul,' and I know that there is a great deal of emotional Christianity which is worth nothing. But it is not that kind of fervour that the Apostle is enjoining here. Whilst it is perfectly true that mere emotion often does co-exist with, and very often leads to, entire negligence as to possessing and manifesting practical excellence, the true relation between these is just the opposite--viz, that this fervour of which I speak, this wide-awakeness and enthusiasm of a spirit all quickened into rapidity of action by the warmth which it has felt from God in Christ, should drive the wheels of life. Boiling water makes steam, does it not? And what is to be done with the steam that comes off the boiling' spirit? You may either let it go roaring through a waste-pipe and do nothing but make a noise and be idly dissipated in the air, or you may lead it into a cylinder and make it lift a piston, and then you will get work out of it. That is what the Apostle desires us to do with our emotion. The lightning goes careering through the sky, but we have harnessed it to tram-cars nowadays, and made it' work for its living,' to carry our letters and light our rooms. Fervour of a Christian spirit is all right when it is yoked to Christian work, and made to draw what else is a heavy chariot. It is not emotion, but it is indolent emotion, that is the curse of much of our fervent' Christianity.
There cannot he too much fervour. There may be too little outlet provided for the fervour to work in. It may all go off in comfortable feeling, in enthusiastic prayers and Amens!' and So be it, Lords!' and the like, or it may come with us into our daily tasks, and make us buckle to with more earnestness, and more continuity. Diligence driven by earnestness, and fervour that works, are the true things.
And surely, surely there cannot be any genuine Christianity--certainly there cannot be any deep Christianity--which is not fervent.
We hear from certain quarters of the Church a great deal about the virtue of moderation. But it seems to me that, if you take into account what Christianity tells us, the sober' feeling is fervent feeling, and tepid feeling is imperfect feeling. I cannot understand any man believing as plain matter-of-fact the truths on which the whole New Testament insists, and keeping himself cool,' or, as our friends call it, moderate.'
Brethren, enthusiasm--which properly means the condition of being dwelt in by a god--is the wise, the reasonable attitude of Christian men, if they believe their own Christianity and are really serving Jesus Christ. They should be diligent in business, fervent' --boiling--in spirit.