Who said 'Keep your friends close and your enemies closer'?

Some believe it was Sun-Tzu, a Chinese general and military strategist (c. 500 BC). However his quotation was different. He said, "Know your enemy and know yourself and you will always be victorious." And while "Michael Corleone" did say that in the movie The Godfather Part II, the actual origin of the quote was from Machiavelli in "The Prince" which is the definitive primer on how to be a dictator.

The first part of the quotation means that you always want to keep your friends close to you because they are people you can trust and rely on.

The second part of this means that your enemies are always going to be out there seeking to harm you so you want to keep an extremely close eye on them, in order to make sure that they are not going to hurt you.

Overall, it means that you should always know what your enemies are doing. As a war tactic, know what the enemy is doing so you don't get ambushed.