"Therefore we do not lose heart, but though our outer man is decaying, yet our inner man is being renewed day by day. For momentary, light affliction is producing for us an eternal weight of glory far beyond all comparison, 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." 2 Corinthians 4:16-18
Have you sometimes wondered if God had forgotten about you, or even if He was against you? The circumstances, both inward and outward, that we face during certain seasons of our lives can really be discouraging to us. Difficulties, disasters, griefs and pains can so mount up as to threaten to overwhelm us. Consider the Apostle Paul. After leading a number of souls to Christ in the city of Corinth and forming them into a thriving new church, another "apostle" or two came along to give these new converts the benefit of their vastly superior knowledge and holiness. One of the criticisms they leveled against Paul was that he suffered a lot. If Paul were really a man of God, they opined, he would be protected from persecution and illnesses. Some preachers seem to have that erroneous notion even today!
But Paul replied by giving a long list of truly terrible sufferings he had endured as he carried out his ministry (2 Corinthians 11:23-29), topping it off by referring to his chronic illness (his "thorn in the flesh"; 12:7-9; possibly an eye ailment), and saying, "Therefore I am well content with weaknesses, with insults, with distresses, with persecutions, with difficulties, for Christ's sake; for when I am weak then I am strong." (2 Corinthians 12:10; see the whole context: chapters 11-12) So now we know what Paul considered "light, momentary afflictions" as he mentioned in the quote above from 2 Corinthians 4:17! They were light and momentary only as compared with "the eternal weight of glory" that these afflictions will ultimately produce for those who trust in Jesus.
Paul, like any of us, did not feel strong when he was undergoing these all-too-frequent times of difficulty and suffering. On the other hand, he had God's assurance that "power is perfected in weakness." (12:9) I think it works like this: physical muscles are only developed and strengthened as they are tested against opposing forces. If we did not have gravity against which our muscles must work to make us move we would soon become so weak we would not be able to stand or move around at all. Astronauts in the space station must exercise against an opposing force in order to maintain muscle tone; otherwise they will not be able to walk or even sit up when they return to earth after just a few weeks or months. Patients confined to bed also experience muscle loss. So, likewise, we must exercise our spiritual muscles against opposing forces or we will lose them altogether. And please remember, just as in physical exercise, when we are exercising our spiritual muscles we will not feel strong but weaker than when we are at rest.
Paul writes that the three things that will endure after we leave this life are: faith, hope and love (1 Corinthians 13:8-13). These three virtues are the sum and substance of godly character. During this life we are developing our spiritual muscles of faith, hope and love. We live in a world that has much that opposes faith, hope and love. Tragedies, injustices and sufferings abound and test our resolve to trust in God's goodness. Disappointments test our hope. Difficult people test our love. God allows us to experience these forces that oppose faith, hope and love in order that faith, hope and love might be strengthened within us as we persevere against opposition. Just as athletes train with weights and regular exercise so that they will be able to perform in competitions, so we are in training so that we might perform well in the ultimate trial - receiving the eternal weight of glory.
You may recall that Satan (meaning, "adversary") was once "the anointed cherub that covers" as depicted on the mercy seat in the Tabernacle. (Ezekiel 28:14; Exodus 25:17-20) Originally, he "had the seal of perfection", and was "full of wisdom and perfect in beauty." (Ezekiel 28:12) If you could have seen him then you would have been tempted to mistake him for God and fall down to worship him. God had bestowed upon him, as well as the other archangels and angels, the "weight of glory", that is, a glorious nature, appearance and position of high responsibility. Perhaps he was given a weight of glory exceeding all others or at least equaled by only a few. This glory was Satan's from the moment of his creation. (28:13) God says to Satan: "You were blameless in your ways from the day you were created until unrighteousness was found in you." (vs. 15) How did this unrighteousness come to be in him and of what did it consist? "Your heart was lifted up because of your beauty; you corrupted your wisdom by reason of your splendor." So the great wisdom and beauty Satan had when he was created became an opportunity for him to become prideful. So what God intended for good to him, Satan turned to evil by his own free will.
So when God created Adam and Eve, He tested them. This was to strengthen their spiritual muscles so they might not fall as Satan did. It was an easy test, but they failed it. So God placed a "curse" upon life in this world that gives us, their descendents, plenty of opportunity to exercise our spiritual muscles of faith, hope and love. Yes, the world, the flesh and the devil are formidable forces opposing the exercise of faith, hope and love but if we persevere against these forces, our ability to overcome them becomes greater and greater. Then, when God bestows upon us the "eternal weight of glory" in the world to come, we will not stagger and fall under it as Satan did. We will not become proud, boastful, arrogant and rebellious as he did. Our "momentary, light afflictions" achieve for us "an eternal weight of glory far beyond all comparison" by giving us the spiritual muscles needed to receive it without danger to our souls or to God's kingdom. God delights to give us His glorious gifts but He also aims to prepare us for it so that His gifts will not prove to be our undoing.
Again, let me repeat, we will not feel strong while we are being tested. Rather, we will feel quite weak while we are trying to move forward against the current of this cursed and fallen world, our corrupt flesh and the devil's temptations. It may be all we can do is merely to "stand" (Ephesians 6:11, 14). And in standing firm against the forces of darkness, we must remember that we are to "be strong in the Lord and in the strength of His might." (vs. 10) One thing will be abundantly clear to us if we do make the effort - that our puny effort alone could not have overcome, that we were enabled to stand by the power of God. This will make us humble and never for a moment trustful in ourselves or boastful of our accomplishments. Thus will we be prepared to hold the tremendous weight of glory awaiting us in eternity. So let us not be discouraged by trials, temptations and our sense of utter weakness, for when we are weak, then we are strong, for our spiritual strength is being perfected in our weakness.