{30} Therefore, my beloved brethren, be ye stedfast, unmoveable, always abounding in the work of the Lord, forasmuch as ye know that your labour is not in vain in the {f} Lord.

(30) An exhortation taken from the profit that ensues, that seeing they understand that the glory of the other life is laid up for faithful workmen, they continue and stand fast in the truth of the doctrine of the resurrection of the dead.

(f) Through the Lord's help and goodness working in us.

People's New Testament

15:58 Therefore, brethren, be ye steadfast, unmoveable. Firm as a rock, devoted to Christian life, for their faith is not vain. Compare 1Co 15:14,17.

Ye know that your labour is not vain in the Lord. Jesus Christ is The Resurrection and the Life (Joh 11:25). The hope of immortality hath sure foundations.

Wesley's Notes

15:58 Be ye steadfast - In yourselves. Unmovable - By others; continually increasing in the work of faith and labour of love. Knowing your labour is not in vain in the Lord - Whatever ye do for his sake shall have its full reward in that day. Let us also endeavour, by cultivating holiness in all its branches, to maintain this hope in its full energy; longing for that glorious day, when, in the utmost extent of the expression, death shall be swallowed up for ever, and millions of voices, after the long silence of the grave, shall burst out at once into that triumphant song, O death, where is thy sting? O hades, where is thy victory?

Jamieson-Fausset-Brown Bible Commentary

58. beloved-Sound doctrine kindles Christian love.

steadfast-not turning aside from the faith of the resurrection of yourselves.

unmovable-not turned aside by others (1Co 15:12; Col 1:23).

the work of the Lord-the promotion of Christ's kingdom (Php 2:30).

not in vain-as the deniers of the resurrection would make it (1Co 15:14, 17).

in the Lord-applying to the whole sentence and its several clauses: Ye, as being in the Lord by faith, know that your labor in the Lord (that is, labor according to His will) is not to be without its reward in the Lord (through His merits and according to His gracious appointment).

Matthew Henry's Concise Commentary

15:51-58 All the saints should not die, but all would be changed. In the gospel, many truths, before hidden in mystery, are made known. Death never shall appear in the regions to which our Lord will bear his risen saints. Therefore let us seek the full assurance of faith and hope, that in the midst of pain, and in the prospect of death, we may think calmly on the horrors of the tomb; assured that our bodies will there sleep, and in the mean time our souls will be present with the Redeemer. Sin gives death all its hurtful power. The sting of death is sin; but Christ, by dying, has taken out this sting; he has made atonement for sin, he has obtained remission of it. The strength of sin is the law. None can answer its demands, endure its curse, or do away his own transgressions. Hence terror and anguish. And hence death is terrible to the unbelieving and the impenitent. Death may seize a believer, but it cannot hold him in its power. How many springs of joy to the saints, and of thanksgiving to God, are opened by the death and resurrection, the sufferings and conquests of the Redeemer! In verse 58, we have an exhortation, that believers should be stedfast, firm in the faith of that gospel which the apostle preached, and they received. Also, to be unmovable in their hope and expectation of this great privilege, of being raised incorruptible and immortal. And to abound in the work of the Lord, always doing the Lord's service, and obeying the Lord's commands. May Christ give us faith, and increase our faith, that we may not only be safe, but joyful and triumphant.