‘For it is written.' Paul now establishes his position from Scripture. This is not just an afterthought. He has been leading up to this. What he has been saying is in fact what the Scripture, God's revealed word to man, itself says, and that is that man's wisdom can only get him into trouble when he is thinking and talking about God.
Compare the commencement of this whole argument in 1 Corinthians 1:18-25. There too he began with ‘it is written' (1 Corinthians 1:19) and referred to this age and this world. There the wisdom of this age and of this world were to be destroyed. Now having considered all it is to bring them low and be their downfall and to pass away as a breath.
For those who think themselves wise, but are not wise in Christ, have a bleak future to look forward to. God's views on earthly wisdom are clearly given in the Scriptures. The thoughts and aims of the ‘wise' are vain, for they finally get them nowhere and accomplish nothing. They are trapped in their own crafty inventions, their own clever reasonings. And they end with nothing, receiving the only end possible for those who have rejected God's wisdom.
‘It is written' signifies reference to the divinely inspired Scriptures. The first Scripture is cited from Job 5:13. Note how this brings out that the Book of Job is in his mind. There we read, ‘He takes the wise in their own craftiness.' The thought is that the wise go racing on with their foolish ideas about God and build them up with great astuteness, only to be brought crashing down. That God interferes to prevent the crafty from achieving their ends, even utilising their own cleverness against them. In the end they are trapped by their own cleverness.
There is clear warning here. Beware of operating away from God's word. Go running off on your own in order to establish how wise you are, and you will finish up falling over yourself. That is in fact what philosophy today has indeed accomplished. It has brought itself to a standstill. God is no longer at the centre of its programme. They disdain the idea that God can be known. Thus, Paul is saying, the truly wise will be those who are not such as to deserve the opprobrium of God by being caught up in their own cleverness.
The second is taken from Psalms 94:11 where we read, ‘The Lord knows the thoughts of man, that they are a breath (that is, temporary and passing).' Paul speaks of ‘the wise' instead of ‘man' because he is directly connecting the verse with his argument. The substitution, however, simply brings out the idea of ‘the thinking man of the world' (the thoughts of man) which is inherent in the Psalm. Both agree that the thoughts of such men are vain. Thus the word of God, says Paul, confirms that men's thoughts in contrast to God's thoughts are nothing but a passing breath.