Seneca the Younger Quote
"What," say you, "are you giving me advice? Indeed, have you already advised yourself, already corrected your own faults? Is this the reason why you have leisure to reform other men?" No, I am not so shameless as to undertake to cure my fellow-men when I am ill myself. I am, however, discussing with you troubles which concern us both, and sharing the remedy with you, just as if we were lying ill in the same hospital.
Letter XXVII - Epistulae Morales ad Lucilium (Moral Letters to Lucilius)