Believing or rejecting is what you decide to do, and it is NOT a work to obey God as scripture teaches.
Heb 11:6
But without faith it is impossible to please him: for he that cometh to God must believe that he is, and that he is a rewarder of them that diligently seek him.
Did you catch that to go to God YOU must believe that He IS.
Appears you have no clue what scripture actually teaches.
Obeying is a work, and so is believing, and it is something we all have to do to be saved.
False teachers made many afraid to say we have to obey and do right actions to be saved, and to stay saved.
The works Paul was speaking about that no longer save are the ceremonial/purification works.
God nailed some things to the cross, but God did not nail obedience to the cross.
We will always have to obey.