The events of the video are of an angry mob setting fire to the Sarhadi Lutheran Church in Mardan, Pakistan from 2012. No one was killed.
A subtitle from the linked video reads
"Mob are Ready to Attack on Mardan Church, Pakistan" (sic)
This was a real event that took place on 21 September 2012, as seen from DAWN, Anglican Ink, The Express Tribune, and CBN.com.
From the blogpost you included with your question
Christians were trapped inside
No evidence that A) anyone was trapped inside or B) that anyone was killed
The Islamic persecution of the Christian minority in Pakistan has become genocide.
Again, no evidence that anyone was killed in the attack. Even the most critical of sources provided at the top (CBN) only claims that
The extremists tried to set the pastor's son afire.
without any citation.
The Western world is silent when Islamists attack Christians but scream when Christians defend themselves.
The Express Tribune directly correlates this attack with the release of a movie entitled The Innocence of Muslims, described by Wikipedia as
(...) an anti-Islamic short film that was written and produced by Nakoula Basseley Nakoula.
What was perceived as denigration of the Islamic prophet Muhammad resulted in demonstrations and violent protests against the video to break out on September 11 in Egypt and spread to other Arab and Muslim nations.
One only needs to read that Wikipedia has a page entitled Reactions to Innocence of Muslims to realize that this was not a targeted terrorist attack, but a large scale protest around the world against a video described by Vanity Fair as
Exceptionally amateurish, with disjointed dialogue, jumpy editing, and performances that would have looked melodramatic even in a silent movie, the clip is clearly designed to offend Muslims, portraying Mohammed as a bloodthirsty murderer and Lothario and pedophile with omnidirectional sexual appetites. “Is the messenger of God gay?” one character asks rhetorically. “Is the master dominant or submissive?”