"بهترین سلاح علیه یک دشمن دشمن دیگری است"

Simplified Meaning:

When facing someone who is against you, the most effective way to deal with them is by finding another person or group who also opposes your enemy. Think of two bullies in a school who both pick on other kids. If the kids being bullied can get the two bullies to focus on each other, they no longer have to deal with being bullied. In history, nations sometimes ally with others who share a common adversary. For example, during World War II, the United States and the Soviet Union joined forces to defeat Nazi Germany, even though they were not friends before and had lots of differences. By fighting a shared threat together, they both became stronger. In everyday life, if you have trouble with a competitor at work, you might partner with someone else who also competes with them. This way, you can both work together to outshine the competitor. Using this strategy helps you deal with the problem more effectively than if you tried to handle it alone.