Most of you have probably heard the neologism "frenemy" to refer to a false friend. The Italians in their wisdom seem to have expressed this long ago in the common proverb: dagli amici mi guardi Iddio che dai nemici mi guardo io. It even rhymes, which is always cool in a proverb.
Translation: may God save me from/keep me from/guard me from my friends, because I can guard/defend myself from my enemies. Why? Because you already know to watch out for your enemies whereas you let your guard down with enemies posing as friends. Or as a catchy tune from long ago said: "your enemy won't do you no harm, 'cause you know where he's coming from... don't let the handshake and the smile fool ya, take my advice I'm only tryin' to school ya...smiling faces tell lies, and that's the truth." It is.
Note that the first verb is a subjunctive and the second one is an indicative. "Iddio" is an archaic or formal word for "Dio."