We have so many enemies of our happiness, the greatest ones are sin and death. Both of them might be too big to defeat on your won but Paul in 1 Corinthians 15:12-28 uses the resurrection of Jesus and our future resurrection to emphasize that these enemies have already been defeated. Jesus has already done it and given you the victory. Your part is to enforce the victory by simply standing your ground, which is your victory ground. In other words, you fight from your position of victory—you don't fight for your victory.