8/2 1 Corinthians 15:58
58 Therefore, my beloved brothers, be steadfast, immovable, always abounding in the work of the Lord, knowing that in the Lord your labor is not in vain.
If we were serving the Lord for this life alone, it would still be the right thing to do. He is worthy to be served and honored with our lives even if life ended at death. Though following Jesus isn't the easiest or the most pleasurable life, it is the best life. His instructions are for our good. But this life is only the beginning, a dot that begins a line that goes on forever.
This chapter points out the promises of God to raise those who believe in Jesus. By His sacrificial death and resurrection He has proved that the power of sin to condemn us has been broken. Death is just the beginning of a glorious eternity with Jesus. That is why Paul tells us to be steadfast, immovable, and always abounding in the work of the Lord. We will be rewarded.
The short time we live in this present world is incomparably brief in the light of eternity. But what we do with this time God has given us affects that eternal condition. Jesus told us to lay up our treasures in heaven (Matthew 6:20). We labor for the Lord because we love Him, but this promise of reward is additional incentive to never give up or slack off. Jesus' resurrection proves that ours is coming.
Consider: Considering the return on investment, we should be joyfully serving our King.