She also encouraged people to contact those in power to make changes.
"We must use our voices to contact the politicians and legislators in our districts and demand social and judicial change," the message read, and included links to help readers find the appropriate congressman to contact.
It's a powerful message from the singer whose Super Bowl halftime show was hailed as a show of solidarity with the Black Lives Matter movement. During that performance, Beyoncé sang "Formation" amid a few dozen dancers marching to the beat in Black Panther berets. (The music video for that song featured Beyoncé singing from the top of a police car, stuck in a New Orleans flood, not to mention a young black child dancing in front of a group of police officers in riot gear.)
"She knows how to make her politics acquiesce to pop's pleasure principles," pop critic Chris Richards wrote after the Super Bowl performance. "Even when our angriest protest artists — Public Enemy, Rage Against the Machine, N.W.A. — sounded like they were gargling the blood of the GOP, they knew how to make it feel good. Beyoncé goes further, foregrounding the pleasure, pushing it from the celebratory toward the ecstatic."
Beyoncé's message stands in stark contrast to some of the other celebrity reactions to the deaths of Sterling and Castile. Former "O.C." actress Mischa Barton, for example, has gotten heat for a tone-deaf Instagram post that featured a photo of her in a bikini on a yacht, cocktail in hand, with a caption that read, in part, "thank god the pigs get caught on camera now."
Other celebrities offered the usual: thoughts, prayers and laments. Beyoncé was one of the few to give some useful advice.