How is it that three of the Rightly Guided Caliphs died by assassination, while the King of Sweden, a country known for the purity of its governance, lives out his life naturally? And is posting this question on Facebook considered a transgression of Islamic law?

These Companions are among the best of creation after the Prophets and Abu Bakr Al-Siddiq. They were afflicted with trials for the sake of Allah, and this is not unprecedented among the righteous. Trials befall Prophets and righteous people for a wisdom, so that they may attain honor and high status, and so that they may be an example for others. The Prophet (peace be upon him) was asked: "Which people are most severely tested?" He said: "The Prophets, then the next best, then the next best. A man is tested according to his faith." Most Prophets were tested, harmed, and some were killed by the disbelievers, as stated in the Holy Quran. So, it is no surprise that these Companions suffered harm and death as a result of the disbelievers' hatred, for the Companions are "strong against the disbelievers, merciful among themselves," and therefore "enrage the disbelievers by them."