‘For this reason we faint not. But though our outward man is decaying, yet our inward man is renewed day by day. For our light affliction, which is for the moment, works for us more and more exceedingly an eternal weight of glory, while we look not at the things which are seen, but at the things which are not seen, for the things which are seen are temporal, but the things which are not seen are eternal.'
And it is because of his concern for the welfare of their spiritual lives, and, we could add, for the welfare of the spiritual lives of all their converts, and because of the grace of God that he knows to be at work, that he and His fellow-workers do not faint or get discouraged. They consider that what they are going through is nothing in the light of eternal blessing, and is momentary in comparison with eternity. Their outward body may be decaying, but what does that matter? Their inward man is being renewed day by day ready for the day of full renewal.
We must not, however, see this as distinguishing body from soul. Paul does not see things that way as he has clearly demonstrated in 1 Corinthians 15. That was the view of his opponents. What Paul means is that a man's body is composed of physical and spiritual elements, and that while the physical elements are decaying and will cease (for flesh and blood cannot inherit the Kingly Rule of God - 1 Corinthians 15:50), the spiritual element is being constantly renewed ready for its resurrection at the last day.
And he then goes on to ask, what is their present ‘light' affliction in view of its glorious purposes and results? Why, it is only temporary and is ever more and more producing for them, to a greater and greater abundance, an eternal weight of glory. Here ‘glory' indicates all the blessings of God of the future, their treasure laid up in Heaven and added to by God. Note the contrast between the ‘light' affliction, and the eternal ‘weight' of glory. What comparison is there between the one and the other?
Thus in view of this they are not looking at what can be seen, they are looking beyond them to the things which cannot be seen, to the attitudes of heart, of love, faith and hope (1 Corinthians 13:13), which are preparing them for the coming day of glory, and to the multiplied blessings that await them once that day has come. And this is because the things that can be seen are only temporal, and passing away, while the things that are not seen are eternal.
In other words, they are setting their minds on things above, where Christ is seated on the right hand of God, and not on things on the earth (Colossians 3:1-4). While on earth their spiritual lives are lived in the heavenly places, in the spiritual realm with Christ (Ephesians 1:19 to Ephesians 2:6), in faith, love and hope. And they are always looking forward to the time when they will be transformed and become men and women with spiritual bodies in heaven, enjoying His perfection for all eternity, enjoying the resting place He is providing for them (John 14:2).