Ayatollah Khamenei view, about Shia and Sunni how they get along and enemies who try to put them apart:
Some people feel that in order to prove themselves, as Shia, they must resort to insulting and cursing the great personalities of Sunni Islam and other denominations. But, this is unnecessary; it goes against the traditions of our infallible Imams (as).
When you bear witness to certain radio and television channels, among the Islamic world, that are launched with the purpose to insult the great personalities of other denominations--under the title of Shi'a Islam--it becomes clear that Britain's Treasury finances them. This is British made Shi'a! No one should believe that development of good Shi'a ideology and strengthening their Shi'a faith [Iman] is dependent on such insults and derogatory manner of speech. This is not productive [Insults, and cursing], this course of action will only produce negative results.
When you use offensive rhetoric, a wall of anger and hard feelings build up around the victims of your insult: Under such circumstances, they cannot even stand to listen to reason. Meanwhile, we have many cogent and logical ideas, ideas that are cherished by anyone given the opportunity to hear them out and ponder upon them; therefore, allow these great ideals to be heard. Allow these ideals an opportunity to seep into the hearts of those who have a different view. When you swear and when you insult those with a different perspective, a dam goes up between both of you, and this results in your beliefs being blocked out. They will not listen.
Under similar circumstances, malicious, dependent mercenary groups who receive money from USA's CIA and other intelligence agencies – groups such as DAESH, Jibhat al-Nusra, and the like – create situations that you witness today in Iraq, Syria, and other countries; and, they do this by using a bunch of ordinary, foolish, and ignorant individuals. This is the enemy’s mission. He [the enemy] is waiting for his opportunity; in fact, he uses every opportunity. You do not have to fall into his trap, especially while we have many truthful, logical and firm ideas.  

Ayatollah Khamenei,
Leader of Islamic revolution of Iran