Former GOP Sen. Ben Sasse reveals stage-4 cancer diagnosis: 'It's a death sentence'

"Advanced pancreatic is nasty stuff; it's a death sentence. But I already had a death sentence before last week too - we all do," he continued.

Sasse, who is just 53 years old, noted, "I've got less time than I'd prefer." 

But he also expressed his eternal hope, noting that he is a Christian.

"As a Christian, the weeks running up to Christmas are a time to orient our hearts toward the hope of what's to come," he wrote. 

"Not an abstract hope in fanciful human goodness; not hope in vague hallmark-sappy spirituality; not a bootstrapped hope in our own strength (what foolishness is the evaporating-muscle I once prided myself in). Nope - often we lazily say 'hope' when what we mean is 'optimism.' To be clear, optimism is great, and it's absolutely necessary, but it's insufficient. It's not the kinda thing that holds up when you tell your daughters you're not going to walk them down the aisle. Nor telling your mom and pops they're gonna bury their son," he noted.

"Those who know ourselves to need a Physician should dang well look forward to enduring beauty and eventual fulfillment. That is, we hope in a real Deliverer - a rescuing God, born at a real time, in a real place. But the eternal city - with foundations and without cancer - is not yet," he wrote.

Sasse noted in his message, "I'll have more to say. I'm not going down without a fight. One sub-part of God's grace is found in the jawdropping advances science has made the past few years in immunotherapy and more. Death and dying aren't the same - the process of dying is still something to be lived. We're zealously embracing a lot of gallows humor in our house, and I've pledged to do my part to run through the irreverent tape.

"But for now, as our family faces the reality of treatments, but more importantly as we celebrate Christmas, we wish you peace: 'The people walking in darkness have seen a great light; on those living in the land of deep darkness a light has dawned….For to us a son is given' (Isaiah 9)," he wrote.