"Remembering without ceasing your work of faith, and labour of love, and patience of hope in our Lord Jesus Christ" -- 1 Thessalonians 1:2-5
And where do these works of faith and love and patience come from?
For it is God which worketh in you both to will and to do of his good pleasure." -- Philippians 2:13
All glory to God alone.
Note that Paul is speaking to saved people.
The 'work of faith' is faith at work (James 2)
We are to bear fruit by using our faith in our Christian walk (Gal.5).
As for Phil.2, that is talking about God working from within you to form Christ in you, the very thing we are Predestinated to become, 'conformed to the image of Christ'.
Our responsibilty (choice) is to yield (Rom.6) our will, so God can work in us.
We will be rewarded for our 'works' at the Judgement seat of Christ (1Cor.3).