"15 Look carefully then how you walk, not as unwise but as wise, 16 making the best use of the time, because the days are evil. 17 Therefore do not be foolish, but understand what the will of the Lord is. 18 And do not get drunk with wine, for that is debauchery, but be filled with the Spirit, 19 addressing one another in psalms and hymns and spiritual songs, singing and making melody to the Lord with your heart, 20 giving thanks always and for everything to God the Father in the name of our Lord Jesus Christ, 21 submitting to one another out of reverence for Christ."
The principle on which we normally order our lives is that of common sense: we think things through rationally. We know the difference between a rational approach to a situation and an emotional one, which latter often proves a disastrous course to follow. And when a man becomes a Christian he does not jettison common sense; rather common sense is sanctified, and therefore much more reliable. We must not distort the meaning of the well-known words 'Trust in the Lord with all thine heart, and lean not unto thine own understanding' into a denial of rational, common sense attitudes, for to 'trust in the Lord with all the heart' means to have a heart - and an understanding - directed, informed and controlled by the Spirit of God. Paul is saying to us distinctly that we must not be mindless in this, or jettison our most valuable possession. Nor must we forget that the Apostle says in Romans 12:1, 2 that it is when we present our bodies a living sacrifice to God that we are most likely to know what is His good and acceptable and perfect will for our lives. When hearts are wholly given over to God we become wonderfully clear-sighted and perceptive, able to identify and isolate the rational from the irrational, able also to discern and resolve the conflict between duty and inclination. Our Lord's words about His sheep knowing His voice (John 10:4) are very pertinent in this. Our real need is to be near enough to the Shepherd to be within hearing distance of His voice!