Hi Wilson, in this context it's just a poetic way of saying "throughout". There are only small semantic differences between "all through" and "throughout". "All through" can connote that an activity is carried out without interruptions. For example, when I say "I worked all through the day", it can imply that I worked without interruptions. In contrast, if I worked "throughout" the day, it can connote that I worked all day long, but with interruptions. But essentially, those two expressions are interchangeable.