Hadiths on requesting others for Dua:

 `Umar (May Allah be pleased with him) said: "I heard Messenger of Allah (peace be upon him) saying, `The best one of the next generation (At-Tabi`un) is a man called Owais, he will have a mother and he will be suffering from leucoderma. Go to him and ask him to pray for forgiveness for you".

[Sahih Muslim].

`Umar bin Al-Khattab (May Allah be pleased with him) reported: I sought permission of the Prophet  (peace be upon him) to perform `Umrah. He granted me leave and said, "Dear brother! Do not forget us in your supplications". (`Umar added): This is something I would not exchange for the whole world.

Another narration is: He (PBUH) said, "Include us, my dear brother, in your supplications.'' (Abu Dawud and At-Tirmidhi, who categorized the Hadith as Hasan Sahih.)

Are Muslims more violent? Research says no.

This study obliterates the myth that Muslims are more violent

Updated by Zack Beauchamp on January 30, 2015, 12:10 p.m. ET @zackbeauchamp zack@vox.com

Whenever the subject of Islamist terrorism comes up, the national conversation almost always circles back to a somewhat bigoted question: are Muslims more violent than other kinds of people because of their religion?

What these conversations usually lack is data; that is, evidence that Muslim societies are actually more violent than other ones. And it turns out, according to UC-Berkeley Professor M. Steven Fish, that judging by murder rates, people in Muslim-majority countries actually tend to be significantly less violent (bolding is mine):

Predominantly, Muslim countries average 2.4 murders per annum per 100,000 people, compared to 7.5 in non-Muslim countries. The percentage of the society that is made up of Muslims is an extraordinarily good predictor of a country's murder rate. More authoritarianism in Muslim countries does not account for the difference. I have found that controlling for political regime in statistical analysis does not change the findings. More Muslims, less homicide.

Fish further fleshed out these findings, for example by re-running the numbers to exclude non-Muslim-majority states with extraordinarily high murder rates (Colombia, El Salvador, Guatemala, Honduras, Jamaica, Lesotho, South Africa, and Venezuela). Countries with lots of Muslims were still less murder prone by a pretty large margin. You can read more details on Fish's findings in his book, titled Are Muslims Distinctive?
If Islam itself were in fact the key cause of Islamist terrorism, you'd expect ordinary Muslims to be more violent than ordinary non-Muslims. There are over a billion believing Muslims globally; if their religion were intrinsically prone to violence, the data would bear that out. In fact, it does nothing of the sort.
Still, there's no denying that Islamist extremist terrorism is a real phenomenon and real problem the rightly receives widespread study. (Fish offers his own argument, that Islamist terrorism is best understood as a reaction to Western foreign policy, but his case is exceedingly unpersuasive.)
That's not to say you can absolve the West completely. Foreign invasions of Muslim countries clearly played a role in fueling the growth of violent Islamist movements. The US-led invasion of Iraq, for example, created widespread chaos and violence, and that chaos and violence gave way to extremism. But the West is only one among a variety of factors at play in the broader 20th and 21st-century trend of Islamist extremism. Other factors have included the prevalence of dictatorship in the Muslim world, Sunni-Shia sectarianism, and, yes, theological doctrines developed by modern Islamists such as Muhammed ibn Abd al-Wahhab and Sayyid Qutb.
In that sense, though, Islam is like almost any other religion: its core tenets can be read both to prohibit and to justify political violence, depending on who's doing the interpreting. That doesn't mean Islam is intrinsically violent. It just means Muslims are people like everyone else. This data should be an important reminder of that distinction.

Source - http://www.vox.com/2015/1/30/7951309/islam-violence