Several things, in this instance faith and works/faith alone.
"...a person is justified by works and not by faith alone” (James 2:24).
''For it is by grace you have been saved, through faith—and this is not from yourselves, it is the gift of God— 9 not by works, so that no one can boast." - Ephesians.
To me that means that a person needs to believe in God and then try to live a life that reflects it. If you sincerely believe in God it would make sense to me that you would also strive to live a lifestyle which reflects it. We all fall short. So it’s about believing and making a real effort to try to live that lifestyle.
Most of the biblical parables are told in a way that require a common sense approach and easy to understand key points. It’s human nature to want to argue over the details. Believing and making an honest attempt to do what is taught is enough. IMO. It had to be because it wouldn’t be possible to write a book long enough to cover every conceivable possibility throughout thousands of years of human history.
Paul stipulates Grace alone, "lest you not boast." If salvation is a gift, a gift is freely given. If a gift is conditional salvation is a trade, not an act of grace or a gift.
