“Abolition transformed the labor market”

“Abolition transformed the labor market.”

is not merely a definitional consequence of abolition.

It connects:

legal change → economic/labor consequence

Therefore it is appropriate to support it with historical evidence.

You might write:

The abolition of slavery transformed labor relations by converting formerly enslaved people into legally free workers.

Then provide appropriate historical scholarship.

“Slavery was abolished → enslaved people were no longer legally slaves”

does not require the same kind of citation because the conclusion follows directly from the legal meaning of abolition.