How do I know I'm not working FOR my salvation?

One thing about Christianity that took me a long time to grapple with is this: I am saved by grace not by works (Ephesians 2:8-9), and yet, I need to prove my faith through my works (James 2:18).  So what does this really look like?

On the outside, it's not easy to tell if someone is doing good work in order to earn their salvation or if they are answering God's call as a result of being saved. As a natural do-er, I felt no need to even decipher the inner motivation for a long time. It felt good to be useful and helpful, and being looked upon positively was pretty cool too.  That is, until I burned out.  And then I got annoyed by others who didn't seem to be working as hard as I was.  Somewhere along the line I had become a legalistic dork who forgot about grace.  I was treating salvation as if it were earned by works rather than given by God.

So, I learnt the difference between a works motivation and a grace motivation the hard way.  Whenever we feel stress and anxiety about the work we do, then start to judge others (remember the story about Mary and Martha in Luke 10:38-42), it is a sure sign that we are working to perform, to earn brownie points from God, from others or from ourselves.  Just as the Israelites during their time as slaves to Egypt in the Old Testament, we work to survive and think we must work to be saved.  

But God did not save us to make us slaves again.  No point returning to Egypt.  He teaches us to work out of faith and obedience to His calling.  We learn to do things motivated by love and gratefulness to him.  We also learn to rest on His divine power that undergirds us whenever he tells us to do anything.  So we feel more free to take risk knowing that success is not dependent on our performance but rather on God's pleasure to deliver.