Following the largest mass shooting in U.S. history, President Obama urges Americans to take "some time for prayer and reflection" this weekend while offering condolences to the families of those who died.

In his weekly address, Obama remembers the victims of the Aurora, Colo., tragedy early Friday morning, calling them lives lost from "senseless" violence that is difficult to understand.

"While we will never know fully what causes someone to take the life of another, we do know what makes that life worth living," Obama says. "The people we lost in Aurora loved, and were loved. They were mothers and fathers; husbands and wives; sisters and brothers; sons and daughters; friends and neighbors. They had hopes for the future and dreams that were not yet fulfilled."

Obama says their loss is a reminder that life is fragile and that what should matter most is "what we do on a daily basis to give our lives meaning and to give our lives purpose."

"This weekend I hope everyone takes some time for prayer and reflection - for the victims of this terrible tragedy, for the people who knew them and loved them, for those who are still struggling to recover, and for all the victims of the less publicized acts of violence that plague our communities on a daily basis," he says.

House Speaker John Boehner joined Obama in offering condolences and prayers for the victims, offering up his weekly address as part of a bipartisan tribute.

"At a time like this, we count our blessings. And as we do, we come to be reminded that the depth of our grief also reveals the depth of our love and our resolve," Boehner says.

"Scripture tells us that the faith that sustains us is 'the substance of things hoped for and the evidence of things not seen.' We may not yet see or fathom comfort for the mourning, but we'll stand by them and we'll stand together, as one nation, in the difficult hours that lie ahead."

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