'Complete' in the Bible

make my joy complete by being of the same mind, having the same love [toward one another], knit together in spirit, intent on one purpose [and living a life that reflects your faith and spreads the gospel—the good news regarding salvation through faith in Christ].

So then, my dear ones, just as you have always obeyed [my instructions with enthusiasm], not only in my presence, but now much more in my absence, continue to work out your salvation [that is, cultivate it, bring it to full effect, actively pursue spiritual maturity] with awe-inspired fear and trembling [using serious caution and critical self-evaluation to avoid anything that might offend God or discredit the name of Christ].

because he came close to death for the work of Christ, risking his life to complete what was lacking in your service to me [which distance prevented you from rendering personally].