Very solemnly did the moral homily to the Asian Christians begin in chapter iv. 17: “This therefore I say and testify in the Lord, that you must no longer walk as the Gentiles walk.” So much has now been said and testified in the intervening paragraphs, by way both of dehortation and exhortation. Here the apostle pauses; and casting his eye over the whole pathway of life he has marked out in this discourse, he bids his readers: “Look then carefully how you walk. Show that you are not fools, but wise to observe your steps and to seize your opportunities in these evil times,--days so perilous that you need your best wisdom and knowledge of God’s will to save you from fatal stumbling.” So far St Paul’s renewed exhortation, in verses 15-17, inculcates care and wary discretion,--the skill that in the strategy of life finds its vantage in unequal ground, that makes opposing winds help forward the seafarer. In this sober wisdom it is likely the Asian Christians were deficient. In many ways, both directly and indirectly, the need of increased thoughtfulness on the readers’ part has been indicated. But there is another side to the Christian nature: it has its moods of exhilaration, as well as of caution and reflection; ardent emotion, eager speech and exultant song are things proper to a high religious life. For these the apostle makes room in verses 18-20, while the three foregoing verses enjoin the circumspection and vigilance that become the good soldier of Christ Jesus. A striking contrast thus arises between the _sobriety_ and the _excitement_ that mark the life of grace. We see with what strictness we must watch over ourselves, and guard the character and interests of the Church; and with what joyousness and holy freedom we may take our part in its communion. Temperament and constitution modify these injunctions in their personal application. The Holy Spirit does not enable us all to speak with equal fervour and freedom, nor to sing with the same tunefulness. His power operates in the limbs of Christ’s body “according to the measure of each single part.” But the self-same Spirit works in both these contrasted ways,--in the sanguine and the melancholic disposition, in the demonstrative and in the reserved, in the quick play of fancy and the brightness and impulsiveness of youth no less than in the sober gait and solid sense of riper age. Let us see how the two opposite aspects of Christian experience are set out in the apostle’s words. I. First of all, upon the one side, _heedfulness_ is enjoined. The children of light must use the light to see their way. To “stumble at noonday” is a proof of folly or blindness. So misusing our light, we shall quickly lose it and return to the paths of darkness.