Thomas Clarkson

I scarcely know of any subject, the contemplation of which is more pleasing, than that of the correction or of the removal of any of the acknowledged evils of life; for while we rejoice to think that the sufferings of our fellow-creatures have been thus, in any instance, relieved, we must rejoice equally to think, that our own moral condition must have been necessarily improved by the change.

— from The history of the rise, progress, and accomplishment of the abolition of the African slave-trade by the British Parliament