Parent model still returns soft deleted child instance

I have a parent model Library which has many Books. Eloquent makes it so easy to define the relationships. I have enabled softdeleting on the book mode using the SoftDeletes trait.

Problem:

When I delete a book instance, the deleted_at attribute on the book instance is set to the current timestamp (as expected).

But when I query all the books that belong to the Library, the result contains all the books, including the ones that were deleted.

I only want to get the books that have not been deleted.

class Library extends Model {
   public function books() {
      return $this->hasMany(Book::class);
   }
}

class Book extends Model {
   use SoftDeletes;
   public function library() {
      return $this->belongsTo(Library::class, 'library_id');
   }
}

$softDeleteBook = Book::find(1);
$softDeleteBook->delete();
$books = Library::find(1)->books;
// $books contains even $softDeleteBook
// I do not want to get $softDeleteBook

via Chebli Mohamed