Sunday was a gorgeous day.

It was the first day of Shavuot, and my shul, like so many others, was celebrating with a picnic.

We’d just finished one of the synagogue’s annual emotional high points. The children — and there are so many children! — walked down the synagogue’s central aisle toward the bimah, as the adults stood for them and sang them in. The children, accompanied by parents, left baskets of brightly colored flowers in front of the ark, the season’s first fruits.

The room itself is brightly colored and that day it glowed, with the sunlight coming through the stained glass and the children generating their own inner-lit rose-color beams.

Then we went to the park, where the toddlers toddled and the babies gurgled and nursed and babbled and slept, and the adults ate and talked and watched the silent ships on the sparkling river. The sky was an impossible blue and the trees an impossible green; the wind moved them so the sharp edges of the shadows bounced and danced.

It was idyllic.

It was the kind of day that evoked the spectacular beauty of September 11, 2001, a day when glorious physical perfection became irrevocably yoked with human evil and degradation.

As we sat there, news of the massacre in Orlando began to percolate. You can keep some people off the internet for some of the time, but you can’t keep them away from newspapers on their doorsteps, and you can’t keep them away from friends and neighbors who don’t undertake the trying challenge of three days offline.

So we heard about what happened. We heard that a man armed with an AR-15-style assault rifle killed 49 people and injured 53 more before he was killed.

How do we make sense of this? We know that it’s a jumble of all sorts of hatreds and threats and sickness and pure evil. We cannot yet detangle the sick strands of Islamicism, jihad, LGBT hatred, the self-hatred of a gay man deeply in denial, the lone wolf ethos that is a part of American culture, and perhaps most immediately, the frightening ease with which people can get assault weapons. (The AR-15-style rifle the murderer used in Orlando was the kind of gun that Adam Lanza used when he slaughtered first-graders in Newtown, Pennsylvania, that James Holmes used when he killed 12 members of the audience at a movie theater in Aurora, Colorado, and that the husband-and-wife murderers Syed Rizwan Farook and Tashfeen Malik used at a holiday party in San Bernardino, California.)

It’s a perfect storm.

One thing that’s clear is that, to be blunt, Omar Mateen was a loser. He was socially awkward, had no friends, beat his wife, could barely hold a job, was investigated by the FBI, but couldn’t even get it to take him seriously. The son of a man who has come close to declaring himself to be president of Afghanistan — in other words, a fabulist — he appears likely to have been gay and to have hated himself for it.

We should be clear. Most Muslims are not jihadists. Most people with undiagnosed mental illnesses are not murderers. Most ideologically- or theologically-driven people are not killers, and most killers are not ideologically or theologically driven. We must learn how to balance extreme vigilance with decency and understanding. We cannot allow ourselves to be blind, and we cannot allow ourselves to be paranoid. We cannot allow ourselves to be divided. We cannot allow ourselves to act out of fear. We cannot allow ourselves to hate each other.

We must hold two things in our minds and hearts at the same time — the knowledge that people are capable of acts of great evil and of great goodness, and that sitting outside in the park in the glorious sunlight with your community is a simple, pure joy that those other truths do not eclipse.