Therefore, my beloved brothers, be steadfast and immovable. Always excel in the work of the Lord, because you know that your labor in the Lord is not in vain.
Therefore they must be steadfast, immovable, always abounding in the Lord's work, knowing that their labor in the Lord is not in vain.
It closes the chapter by joining resurrection to endurance in labor.
50Now I declare to you, brothers, that flesh and blood cannot inherit the kingdom of God, nor does the perishable inherit the imperishable. 51Listen, I tell you a mystery: We will not all sleep, but we will all be changed — 52in an instant, in the twinkling of an eye, at the last trumpet. For the trumpet will sound, the dead will be raised imperishable, and we will be changed. 53For the perishable must be clothed with the imperishable, and the mortal with immortality. 54When the perishable has been clothed with the imperishable and the mortal with immortality, then the saying that is written will come to pass: “Death has been swallowed up in victory.” 55“Where, O Death, is your victory? 56The sting of death is sin, and the power of sin is the law. 57But thanks be to God, who gives us the victory through our Lord Jesus Christ! 58Therefore, my beloved brothers, be steadfast and immovable. Always excel in the work of the Lord, because you know that your labor in the Lord is not in vain.