Salvation is by grace through faith, and is a gift of God, not by works (Eph 2:8). However, there is a reward for believers doing good works. Good works are not just disciplines for our benefit, by which we enjoy God, as some people claim. Paul does not say it is God building something, it is us building something, it is man doing the works (1 Cor 3:12-15), and that is what is rewarded. The very important thing here, though, is that the foundation on which these works are built must be Christ (1 Cor 3:11) and that it is the right sort of work (v.13). So let’s not stop at the foundation, when we have to build on this foundation if we are to be rewarded. See also Romans 2:6-10, Luke 6:35, Eph 6:8, Rev 22:12 for more on rewards for works. So in a sense it is our choice whether we do good works. You are still saved by faith, without works, but the degree of your reward is according to your good works.
Neglecting to say that good works are needed for a reward is unbiblical and can create lazy, disobedient Christians who God can do nothing with. Reward according to works needs to be taught, along with the importance of building on the foundation of Jesus Christ, building the right sort of work, hearing God, doing what he is doing, and obedience to Him.