A Commentary by John Stott

Matthew 5:13. You are the salt of the earth.

The affirmation is straightforward: ‘You are the salt of the world’ (NEB). This means that, when each community is itself and is true to itself, the world decays like rotten fish or meat, while the church can hinder its decay.

Of course God has set other restraining influences in the community. He has himself established certain institutions in his common grace, which curb man’s selfish tendencies and prevent society from slipping into anarchy. Chief among these are the state (with its authority to frame and enforce laws) and the home (including marriage and family life). These exert a wholesome influence in the community. Nevertheless, God intends the most powerful of all restraints within sinful society to be his own redeemed, regenerate and righteous people. As R.V.G.Tasker puts it, the disciples are ‘to be a moral disinfectant in a world where moral standards are low, constantly changing, or non-existent’. The effectiveness of salt, however, is conditional: it must retain its saltiness. Now, strictly speaking, salt can never lose its saltiness. I am given to understand that sodium chloride is a very stable chemical compound, which is resistant to nearly every attack. Nevertheless it can become contaminated by mixture with impurities, and then it becomes useless, even dangerous. (I am indebted to Mr. G.J.Hobson, a chemist in Camforth, Lancashire, for writing to me in August 1972 about this, in order to correct an earlier blunder of mine and to supply a lack in my scientific knowledge.) Desalted salt is unfit even for manure i.e. the compost heap. Dr David Turk has suggested to me that what was then popularly called ‘salt’ was in fact a white powder (perhaps from around the Dead Sea) which, while containing sodium chloride, also contained much else, since, in those days, there were no refineries. Of this dust the sodium chloride was probably the most soluble component and so was easily washed out. The residue of white powder still looked like salt, and was doubtless still called salt, but it neither tasted nor acted like salt. It was just road dust.

So too a Christian. ‘Have salt in yourselves,’ Jesus said on another occasion. (Mk.9:50) Christian saltiness is Christian character as depicted in the beatitudes, committed Christian discipleship exemplified in both deed and word (Lk.14:34, 35; Col.4:6). For effectiveness the Christian must retain his Christlikeness, as salt must retain its saltiness. If Christians become assimilated to non-Christians and contaminated by the impurities of the world, they lose their influence. The influence of Christians in and on society depends on their being distinct, not identical. Dr Lloyd-Jones emphasizes this: ‘The glory of the gospel is that when the church is absolutely different from the world, she invariably attracts it. It is then that the world is made to listen to her message, though it may hate it at first.’ Otherwise if we Christians are indistinguishable from non-Christians, we are useless. We might as well be discarded like saltless salt, ‘thrown out and trodden underfoot by men’. ‘But what a downcome,’ comments A.B.Bruce, ‘from being saviours of society to supplying materials for footpaths!

Tomorrow: Matthew. 5:14-16. The light of the world.

The John Stott Bible Study is taken from The Message of the Sermon on the Mount. The Bible Speaks Today John Stott. Used by permission of Inter-Varsity Press UK, Nottingham. All rights reserved.