What parts of the Bible are applicable for us today?

Listener question: How do we know which parts of the Bible are still applicable in modern times and which are outdated? Can we accept the Bible in part or should we accept it in full? If the former, who decides? Is it up to individuals? If so, doesn't that render Biblical truth irrelevant, as everyone can just pick the parts they want to adhere to and ignore others? Audio Production by Podsworth Media - https://podsworth.com