It is not for the sake of earthly or heavenly rewards that we run our race but rather that we might win Jesus. He is our focus and the goal is to be like Him. He is the measure and stature to which we are to attain. From him and to him and for him are all things. We belong to Him and in Him we also share all things since He is the first born to receive a full inheritance among men. We owe everything to Him who saved us and can boast of nothing for He is the author and finisher of our faith. It is by God's grace that we are saved and we can add nothing to that.
Having saved us God has decreed or commanded that we should do the good works that He planned for us before we were even born. Righteous works that bring Him glory by accomplishing His will while we are still on this earth. Works that He planned and approves of and not our own works. Only His works are righteous works.
God is not unjust or evil, like a man, that he would neglect or take advantage of those who obey and do His work.  He will richly reward all His servants who prove faithful to do what He commands them. God is not only generous but he is fair and righteous to give each according to the work he does. To each of us has been given a task for which we are held accountable. God will judge our work and He will decide which is rewarded what is disqualified and what was just our reasonable service.
We do not gain heaven and all it's benefits by our works but God is not unaware of what we do and did out of love for Him and our neighbor when we meet Him face to face and He says to us "Well done - good and faithful servant".