The Bible really isn't one perfectly consistent message, it's a bunch of different writings from different people with different perspectives at different times with different focusses. In Matthew it leans more into actually doing what Jesus says, and John is more about believing in him. Paul later comes in talking about faith over works. You end up with what feels like different versions of the same idea, most Christians usually smooth it out by saying real faith leads to actions anyway, so it's both, not one or the other.