Well, like so many things I lose, I only find something when I stop looking so hard and ask for help
For anyone interested, here is the quote:
"And therefore we must piously and cautiously watch, so that when necessity shall compel us to find fault with or rebuke any one, we may reflect first whether the fault is such as we have never had, or one from which we have now become free; and if we have never had it, let us reflect that we are men, and might have had it; but if we have had it, and are now free from it, let the common infirmity touch the memory, that not hatred but pity may go before that fault-finding or administering of rebuke: so that whether it shall serve for the conversion of him on whose account we do it, or for his perversion (for the issue is uncertain), we at least from the singleness of our eye may be free from care. If, however, on reflection, we find ourselves involved in the same fault as he is whom we were preparing to censure, let us not censure nor rebuke; but yet let us mourn deeply over the case, and let us invite him not to obey us, but to join us in a common effort."
This is from Blessed Augustines Book on the Sermon on the Mount, Book Two chapter 19. There is a lot of other good advice in that same chapter worth praying over but this is the essence of it.
David