To succeed you need a friend, to be very successful you need the enemy.

要想成功你需要的朋友，要想非常成功你需要的敌人。

youdao

He faced the enemy valiantly, shuned no difficulties and dangers and would not hesitate to lay down his life if need be.

他英勇对敌，不避艰险，赴汤蹈火在所不计。

《新英汉大辞典》

We need to understand more of these attacks of the enemy upon our spirits and how to resist them.

今天我们需要知道仇敌怎样在我们的里面施行攻击，我们应当怎样去抵挡他。

youdao

And in all we do, I will ensure that our commanders on the ground have the troops and flexibility they need to defeat the enemy.

CNN: Text of President Bush's speech

Yet diplomatic recognition need not be the enemy of morality.

ECONOMIST: Unban the Taliban

When you're in a combat zone, you need to be focusing all of your energies on fighting the enemy.

CNN: U.S. sailor: Don't deport my wife