I Corinthians 15:55-58
(55) “Death is swallowed up in victory. O death, where is your victory? O death, where is your sting?” (56) For sin is the sting that results in death, and the law gives sin its power. (57) But thank God! He gives us victory over sin and death through our Lord Jesus Christ. (58) So, my dear brothers and sisters, be strong and immovable. Always work enthusiastically for the Lord, for you know that nothing you do for the Lord is ever useless.

Not in Vain 

1. Christ’s victory validates our work
2. Gods Spirit enables our work
3. Our Heavenly Father evaluates the impact of of our work