The poster as a whole is self-explanatory. 

The calligraphic logo in the upper-right corner is for the Al Saff Media Group. "Al-Saff" is also the name given to Chapter 61 of the Koran, which carries the general theme of exhorting Muslims to adopt sincerity in their faith, and to struggle with their lives in the cause of Allah. As a reward, they will earn immunity from Allah's punishment, forgiveness of their sins, and the eternal Paradise in the hereafter.

It is unknown if this poster holds any direct nexus to yesterday's mass shooting at the Gilroy Garlic Festival in Gilroy, CA.