One fake friend can do more harm than 10 enemies... Be smart choosing your friends.

An enemy forgiven is more dangerous than a thousand foes.

A false friend is more dangerous than an open enemy

Do not forget that a traitor within our ranks, known to us, can do more harm to the enemy than a loyal man can do good to us.

He who has a thousand friends has not a friend to spare, while he who has one enemy will meet him everywhere.

519. One enemy is too much.

Evil companions bring more hurt than profit.

"An Eastern poet, Ali Ben Abu Taleb, writes with sad truth, — "He who has a thousand friends has not a friend to spare,
And he who has one enemy shall meet him everywhere.

One single war — we all know — may be productive of more evil, immediate and subsequent, than hundreds of years of the unchecked action of the mutual-aid principle may be productive of good.

A foolish friend may cause more woe
Than could, indeed, the wisest foe.

For every ten jokes, thou hast got a hundred enemies.

A wise man gets more use from his enemies than a fool from his friends.

It is easier to forgive an Enemy than to forgive a Friend.

Nothing is as dangerous as an ignorant friend; a wise enemy is to be preferred.