Translations:الخطية الأصلية/62/en

• It means linking the sin of all human beings to the sin of Adam, because Adam’s sin affected all of Adam’s descendants, as he is the father of all, containing all in his loins.

All mankind was in the loins of Adam when he sinned. Adam sinned, but not as a person, but as a representative and head of the entire human race. As an example of Christ - the second Adam - who also offered himself on behalf of the entire human race.