1 Corinthians 15:58

Therefore my beloved brethren
This is the conclusion of the whole, and contains the use the apostle makes of the above doctrine, addressing the saints at Corinth in the most tender and affectionate manner; owning the spiritual relation they stood in to him, and expressing the great love he had for them, which filled him with a concern for them, that they might be both sound in principle, and right in practice, and continue so:

be ye steadfast, unmoveable;
in all the doctrines of the Gospel, and particularly in this of the resurrection of the dead, which he had been labouring throughout the whole chapter:

always abounding in the work of the Lord;
going on in it, being more and more in the practice of it; either in the work of the ministry, which some of them were in, to which the Lord had called them, and for which he had fitted and qualified them, and in which his glory was greatly concerned, and therefore called his work; or any other work, even all good works, which the Lord commands, requires, calls his people to, and strengthens them to perform: which when they do they may be said to abound, and to be fruitful in every good work: and for their encouragement it is added,

forasmuch as ye know that your labour is not in vain in the Lord;
the labour of such who were in the ministry was not in vain, but was by the Lord made useful for the conversion of sinners, and the edification of saints, who would be their joy, and crown of rejoicing another day; and which must be no small encouragement to labour; and labour in any kind of good work has here its usefulness: it is profitable unto men, and though not meritorious of eternal life, yet the good works of the saints will follow them; Christ will not forget their work and labour of love which they have shown to his name and people, but will take notice of them as fruits of his own grace, and bestow his rewards upon them, though not in a way of debt, but of grace; which the doctrine of the resurrection assures of, and encourages to hope for; and so must he a friend to the practice of good works, as the contrary doctrine must be an obstruction to them.