'Work' in the Bible

For I am confident of this very thing, that He who began a good work in you will perfect it until the day of Christ Jesus.

So then, my beloved, just as you have always obeyed, not as in my presence only, but now much more in my absence, work out your salvation with fear and trembling;

for it is God who is at work in you, both to will and to work for His good pleasure.

because he came close to death for the work of Christ, risking his life to complete what was deficient in your service to me.