For we are God's workmanship, created in Christ Jesus to do good works, which God prepared in advance for us to do.Good works are:
1. What Christians are to do as the result of Him working in us.
2. Designated for us in advance.
God has prepared certain good works for us to do and His work in us gives us the ability to do them, which means there is no room for boasting on our part.
That we have nothing to boast about isn't a new idea introduced in this verse. In fact, it is a followup: In the two verses prior to this (2:8-9), we see that our salvation is a merciful gift from God so that we can't boast. Interestingly, the good works we do, like our salvation, are to His credit. It's a package deal. God alone gets the credit for our salvation and our good works.