"17 Now this I say and testify in the Lord, that you must no longer walk as the Gentiles do, in the futility of their minds. 18 They are darkened in their understanding, alienated from the life of God because of the ignorance that is in them, due to their hardness of heart. 19 They have become callous and have given themselves up to sensuality, greedy to practice every kind of impurity. 20 But that is not the way you learned Christ!— 21 assuming that you have heard about him and were taught in him, as the truth is in Jesus, 22 to put off your old self,[f] which belongs to your former manner of life and is corrupt through deceitful desires,23 and to be renewed in the spirit of your minds, 24 and to put on the new self, created after the likeness of God in true righteousness and holiness."
Ephesians 4:17-24
Having indicated in the first half of the chapter the provision Christ has made for our growth and development into full maturity of life, Paul reverts once more to the exhortation to walk worthy of our vocation (which he began in 4:1). There is a sense in which what the Apostle has said in 4:4-16 is a tangent in his thought, like the tangent in 3:2-12, and it is a measure of how important he considers it to emphasise the indicatives of the faith, and the nature of the divine provision for all our needs, that he keeps coming back again and again to these indicatives, so as to get home unmistakably to our thinking that all Christian behaviour depends and rests on what God has given us in Christ. The exhortation to a worthy walk is therefore doubly based on the divine provision - in chs 1-3 Paul has spoken of the wealth that is ours in Christ, and the exalted nature of our position in Him; and in 4:4-16 he likewise shows the bountiful way in which the Lord has undertaken to 'make over' that wealth to His people, namely by the institution of the gifts of ministry in the Church. This, in fact, serves to highlight and reinforce the appeal (begun in 4:1-3 and taken up again in 4:17ff) to walk worthy of such a vocation, when such abundant resources are at our disposal to make this possible.
That is the first thing we are to learn from this passage, and the second thing is - and for this we need to look on a bit, beyond the end of the chapter and into chapter 5 - that Paul first of all makes a number of negative observations and follows them with positive ones. These can be summed up by underlining the words 'walk not' in 4:17, and the word 'walk' in 5:2. This is a significant point, which we shall continue to look at in tomorrow's Note.